Re: Topband: Radials on ground

[Carl Braun]

Topbanders

Here is my favorite article on ground radials by Al Christman K3LC.  
https://ncjweb.com/bonus-content/k3lcmaxgainradials.pdf

Great reading but I continue to add more radials thus exceeding Al's suggested 
number.  I also use Eight 3" aluminum irrigation pipes under each vertical that 
are 30' long in conjunction with 50 100' long wire radials.  I use the 
irrigation pipe as radials rather than stack them behind the garage waiting for 
the price of aluminum to peak.

73, Carl W9LF


-Original Message-
From: Topband  On Behalf 
Of Jim Brown
Sent: Friday, January 7, 2022 12:36 PM
To: topband@contesting.com
Subject: Re: Topband: Radials on ground

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On 1/7/2022 6:14 AM, Pete Smith N4ZR wrote:
> is the size of wire used for on-the-ground radials - or elevated 
> radials for that matter - significant?

The only significance is their mechanical characteristics to withstand physical 
conditions.

 > at least as compared to feeding the antenna against a single ground  > rod.

The earth is a big resistor. We do NOT want a connection to it, except for 
lightning protection. Indeed, radials have two functions -- to provide a low 
resistance path for the antenna's return current, and to SHIELD the antenna's 
field from the lossy earth.

The only antennas whose performance benefit from an earth connection are 
receiving antennas.

Conversations here can point us to consider other options, but are not a 
substitute for serious study of fundamentals. Real understanding of how stuff 
works is better obtained by study of the Handbook, the Antenna Book, and the 
ON4UN book.

Rudy Severns, N6LF, has done a LOT of excellent work, in the form of 
interactive modeling concepts, building and measuring radial systems, modeling 
some more, and building measuring some more, then publishing what he's done and 
what he's learned. It's also well worth studying.
https://nam12.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.antennasbyn6lf.com%2Fdata=04%7C01%7CCarl.Braun%40cattron.com%7Cd80402cf63804d67fdd808d9d20c996c%7Ce3db7da86f894250a548d36f358a7d2a%7C0%7C0%7C637771774496971841%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000sdata=626vCzmEvqb1EpFh3eoEfr75LZDkDdenVM5y5VqU8IE%3Dreserved=0
  Going to his site to find this link, I see that since my last visit, he's 
published some work on loop and loop on ground RX antennas.

Almost ten years ago, I summarized what I'd learned from others on the topic of 
160M antenna systems for limited space in a talk I've done at Visalia, 
Pacificon, and for several clubs including NCCC. Most of it is about radial and 
counterpoise systems. None of it is original work on my part. The slides are 
here. 
https://nam12.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.antennasbyn6lf.com%2Fdata=04%7C01%7CCarl.Braun%40cattron.com%7Cd80402cf63804d67fdd808d9d20c996c%7Ce3db7da86f894250a548d36f358a7d2a%7C0%7C0%7C637771774496971841%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000sdata=626vCzmEvqb1EpFh3eoEfr75LZDkDdenVM5y5VqU8IE%3Dreserved=0

73, Jim K9YC
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Re: Topband: Wednesday Night Activity

[Carl Braun]

Hello Roger and Topbanders

I heard G3YRO last night at 0024. You were good copy at S4 with heavy qsb. I 
threw every watt I had (120w) toward G3 but didn’t make it. You did send me a ? 
but no contact.

Hang in there. I’ll have the amp cooking on 160 soon and we’ll get a contact in 
the log soon.

73 from Wisconsin where it is -18c now.

Carl W9LF

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From: Topband  on behalf 
of Roger Kennedy 
Sent: Friday, December 31, 2021 12:59:46 PM
To: topband@contesting.com 
Subject: Topband: Wednesday Night Activity

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Well conditions had been pretty good all week up to Wednesday . . . I had
plenty of QSOs right across the US, and was getting NA RBN S/N reports
between +30 to 40dB, which is as good as it gets.

However on Wednesday night I came on the band around Z, but saw that my
RBN reports were way down - I figured this was likely to be due to QRN
rather than propagation. So I didn't stay on very long. I tried again around
0300, but it was much the same.

Incidentally, as I have mentioned previously, there always used to be a big
peak on 160m signals around our Sunrise . . . but I find the reverse is true
these days. Best reports from across North America are around 00.30 for me .
. . signals drop off at least 10dB as you get near our Sunrise. (and I've
noticed the same on receive, listening to lots of stations during the
contests). So I rarely bother coming back on at Sunrise.

Anyway, hopefully there will be lots of activity next Wednesday night.

Happy New Year to everyone !

73 Roger G3YRO

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Re: Topband: Great condx on 160M Dec 24, 21 - 0500Z-0600Z+

[Carl Braun]

Hello Dan and Topbanders

Great condx here in WI last night. Lots of activity from EU. ON4CT and OM2XW 
were particularly strong.  S7 signals typical.

I’m running two base loaded 70’ verticals in phase 1/8 spacing for general Omni 
TX/RX and 130w on this end.

MX and HNY

Carl W9LF

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From: Topband  on behalf 
of W7Rf 
Sent: Friday, December 24, 2021 12:30:05 AM
To: Topband 
Subject: Topband: Great condx on 160M Dec 24, 21 - 0500Z-0600Z+

CAUTION: This email originated outside of the organization. This message might 
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nor links in the message.

 Very nice condx now, worked over a dozen EU from Colorado, strong signals and 
low noise. Some over S9.

Modest 160M station here, 165 foot inverted L and 1100 foot loop up 65 feet.

500 watts tonight.



73 to all

Merry Christmas and Happy New Year



Dan W7RF








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Re: Topband: cheap radial wire?

[Carl Braun]

Greg and list

I started from scratch with my two element ground mounted vertical array. I’ve 
set quite a few radials and installing more before the snow hits here in the 
north woods.

After doing lots of shopping for surplus wire I’ve settled on private sellers 
on eBay. I just purchased two 1000’ spools of 14ga stranded for $90 each. This 
was NOS wire and is made in USA. Free shipping on these heavy spools too.

Good luck with your search!

Carl W9LF

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From: Topband  on behalf 
of List Mail 
Sent: Monday, November 8, 2021 5:49:32 PM
To: Greg Davis ; topband@contesting.com 

Subject: Re: Topband: cheap radial wire?

CAUTION: This email originated outside of the organization. This message might 
not be safe, use caution in opening it. If in doubt, do not open the attachment 
nor links in the message.

I can only relate my experience in Australia, where wire is expensive.
After investigating bulk wire from manufacturers here, electrical wholesalers, 
etc., I ended up buying spools of “Building Wire”. I purchased 20 x 100 m rolls 
of 1.5 mm building wire from an electrical wholesaler at AUD29/roll. The 
7-strand wire is fairly small, but with the PVC insulation, quite good to 
handle, doesn’t spring or coil and I buried it with a fitting I constructed for 
the tractor.
Good luck, Luke VK3HJ.

Sent from Mail for Windows

From: Greg Davis
Sent: Tuesday, 9 November 2021 9:20 AM
To: topband@contesting.com
Subject: Topband: cheap radial wire?

Hello Topbanders,

I recently reached out directly to a few people who had posted
recently(ish) to this email reflector who had described purchasing large
amounts of wire for radials at a (relative) bargain price.

However, after a couple of weeks of waiting, none of those emails have been
responded to. I've got a new-and-improved plan for my 160m vertical in my
back yard, but, at this moment in time, the biggest thing holding me back
is the wire for a sufficient radial field. Do any of you have spools of
wire you're willing to sell to me if the price is right? Or suggestions for
me where I can purchase it for a reasonable price?

Thank you.

73 de Greg N3ZL
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Re: Topband: S9OK 160m EU

[Carl Braun]

S9OK was light with me last night here in northern WI but I could copy.  
Listened to the pile up...up...upwith lots of east coasters calling from NA 
but hearing VERY few stations west of me.

I was listening on an 80m vertical so less than ideal RX antenna.

73,

Carl W9LF

-Original Message-
From: Topband  On Behalf 
Of Bill Weaver
Sent: Wednesday, October 6, 2021 8:33 AM
Cc: topband reflector 
Subject: Re: Topband: S9OK 160m EU

CAUTION: This email originated outside of the organization. This message might 
not be safe, use caution in opening it. If in doubt, do not open the attachment 
nor links in the message.

Andy,
You were a fairly solid 529 into Central KY on my GAP vertical (Poor RX 
antenna). I gave you a few calls with no luck (apparently a bad TX antenna also 
:)). S9OK was just under the noise level. Work begins this weekend on a HI-Z 
4-square :).

73,
Bill WE5P

Comfortably Numb

> On Oct 6, 2021, at 00:03, Andree DL8LAS via Topband  
> wrote:
>
> Hey topbanders, nice signal from S9OK this morning in DL. Worked also first 
> west coast this season. N7UA was real 559 today. Here is a short clip from 
> S9OK. 
> https://nam12.safelinks.protection.outlook.com/?url=https%3A%2F%2Fyoutu.be%2Fv-O-PGtM9oAdata=04%7C01%7CCarl.Braun%40cattron.com%7C51cb4ebad3d34e18bafa08d988ce0973%7Ce3db7da86f894250a548d36f358a7d2a%7C0%7C0%7C637691242305371802%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000sdata=%2BDwinG0fiZ9cjcdxJLQZg%2Fjz9nzNZ2Ua7sSNdozhVtQ%3Dreserved=0
> 73 Andy DL8LAS 
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Topband: Ground Radial question - Perimeter connections

[Carl Braun]

Hello Topbanders

Another question for the experts...

When installing ground radials on a ground mounted vertical, how critical is it 
to connect those radials together at the far ends?  Some technical references 
show the outer tips of the ground radials connected with what they call 
'perimeter connections' and I'm wondering if these connections really add value 
to the ground radial screen.   Has anyone modeled a single vertical or an array 
with and without these 'perimeter connections' to determine if they are worth 
the time and effort to install?  Please advise.

Thank you

Carl W9LF


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Re: Topband: New Subject: 160M array feedline question

[Carl Braun]

Topbanders

Thanks to all who responded

I received a lot of good advice and will be taking it.  Specifically, the 
advice to bury the hardline rather than elevate it.

Some brought up the idea of my ground mounted radials becoming submerged in 
fresh water...however, that would only take place for a week or less during the 
spring here and, it would only happen if we had a slow snow pack melt and rain 
at the same time.  This happened here two years ago but only lasted for a week 
or so.

I am sure to have more questions as this project matures.  In the meantime, I 
will continue to work with my modified 80/160 Butternut vertical that's stuck 
in the snow.  It uses 4 pieces of 30' irrigation tubing for radials as well as 
some wayward wires to create the ground screen.  No amplifier. This winter I 
have 22 countries on 160 with it.  Looking forward to the array!

Thanks again

Carl W9LF

From: Carl Braun
Sent: Sunday, March 21, 2021 3:26 PM
To: topband@contesting.com
Subject: New Subject: 160M array feedline question


Hello Topbanders

I am currently awaiting the snow to melt here in the Northwoods of Wisconsin 
before starting the construction of my low band vertical array.  My verticals 
will be mounted in a low ground area near a lake and the area tends to get wet 
and sometimes floods in the early spring.  Water levels could reach 6" to 12" 
above ground.  My concerns relate to the hardline coaxial cable that will run 
from my lighting arrestor panel at the outside of my shack to the center of the 
two element vertical array which is 250' away.  I will be using 1 5/8" hardline 
that I was able to snag for a very good deal but am concerned about having the 
cable lying on the ground and possible become submerged should we get 
significant rain with the snow melt.

My plan is to elevate the feedline approximately 24" above the ground using old 
sections of Rohn 25 tower spaced every 10' or so.  Each vertically mounted 5' 
chunk of Rohn 25 will be buried 2' into the ground have a 3' 2x6 board laying 
horizontally across the tower that would act as a coaxial "shelf" that will 
keep the hardline out of the water and prevent any significant drooping between 
these Rohn support sections.

My question for the forum is related to the fact that I will have an elevated 
coaxial feedline with two ground mounted vertical antennas.  I plan to use an 
UNUN or similar line isolator/choke that would keep the hardline from becoming 
a extra radial.  Any thoughts from the forum on this set up? Any extra 
precautions I should take to keep return currents from flowing on the feedline?

Thanks in advance for any suggestions.

Carl W9LF

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Topband: New Subject: 160M array feedline question

[Carl Braun]

Hello Topbanders

I am currently awaiting the snow to melt here in the Northwoods of Wisconsin 
before starting the construction of my low band vertical array.  My verticals 
will be mounted in a low ground area near a lake and the area tends to get wet 
and sometimes floods in the early spring.  Water levels could reach 6" to 12" 
above ground.  My concerns relate to the hardline coaxial cable that will run 
from my lighting arrestor panel at the outside of my shack to the center of the 
two element vertical array which is 250' away.  I will be using 1 5/8" hardline 
that I was able to snag for a very good deal but am concerned about having the 
cable lying on the ground and possible become submerged should we get 
significant rain with the snow melt.

My plan is to elevate the feedline approximately 24" above the ground using old 
sections of Rohn 25 tower spaced every 10' or so.  Each vertically mounted 5' 
chunk of Rohn 25 will be buried 2' into the ground have a 3' 2x6 board laying 
horizontally across the tower that would act as a coaxial "shelf" that will 
keep the hardline out of the water and prevent any significant drooping between 
these Rohn support sections.

My question for the forum is related to the fact that I will have an elevated 
coaxial feedline with two ground mounted vertical antennas.  I plan to use an 
UNUN or similar line isolator/choke that would keep the hardline from becoming 
a extra radial.  Any thoughts from the forum on this set up? Any extra 
precautions I should take to keep return currents from flowing on the feedline?

Thanks in advance for any suggestions.

Carl W9LF

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Re: Topband: inv. L

[Carl Braun]

Art

I use two 65' verticals on 40/80/160.  HALF WAVE tall (electrically) and 
spacing on 40m with LC network at the base to tune...QUARTER WAVE tall on 80 
with same spacing and EIGHTH WAVE tall and spacing on 160m.  

Both verticals are fed in phase on 160 now but I have plans to add an LC phaser 
that should allow for some directivity.  Current pattern seems to be omni with 
the verticals being so close to one another.  I did try inserting a delay line 
into the scheme with some (2-3 db) directivity seen and may continue to 
experiment with that angle until I build the LC Phaser.

AG6X



-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Art Snapper
Sent: Monday, October 17, 2016 8:17 AM
To: 160
Subject: Topband: inv. L

I was considering adding a second vertical element to my 160 inverted L.
This one would be roughly a quarter wave tall for use on 80.

I tried modelling in Eznec, but wasn't comfortable with the results. I may have 
screwed it up.

Has anyone tried it for real? Is it a big compromise on either band? Would a 
switch at the feedpoint have any benefit?

My inverted L has about 50 radials.

73
Art NK8X
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Re: Topband: 2 element vertical for 80m with 1/8wavelength spacing

[Carl Braun]

John and fellow Topbanders

I'm running a similar setup...and have my two 65' verticals spaced at 71'.  I 
have custom matching circuits that allow me to use the verticals on 160m 
(inductively base-loaded) at 1/8 wl spacing...80m (1/4 wl tall) at 1/4 wl 
spacing...and 40m (1/2wl tall) at 1/2 wl spacing.

The antenna is basically OMNI directional on 160 but offers up to 20db F/B on 
80 @ 3-4db gain and even larger F/B and gain in 40.

Each vertical is aluminum tubing tapering from 4" at the base to 1" at the top 
and sits above 100 radials.

Don, AE7H, was kind enough to send over schematics and magazine articles 
featuring the "Elsie Phaser"...that implements a variable capacitor, a variable 
inductor and a DPDT relay.  He claims big F/B and gain when tuned vs the 
traditional delay line approach that's featured in John's (ON4UN) book.  I'm 
eager to get moving on that project and have it ready for the coming DX season. 
 Contact me if you'd like details on this gadget.

I love the "tri-band" antenna and maintaining it involves much less drama than 
the two element 75m yagi I had at 95'.

73

Carl AG6X

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of John Kaufmann
Sent: Tuesday, April 19, 2016 5:26 PM
To: 'topband'
Subject: Re: Topband: 2 element vertical for 80m with 1/8wavelength spacing

I also use a vertical phased array with 1/8-wave spacing on 80m.  I did this 
because of limited space.  Like PE5T describes in his post below, I used the 
method in ON4UN's book and originally described in a series of articles by K2BT 
in Ham Radio magazine (no longer in publication) in the 1980's.  I designed my 
own custom L-C circuits for phasing and matching.  I don't think there is a 
simple plug-and-play solution that would provide good performance at close 
spacing like this.

As Kees says, the impedances at close spacing are low and you have to work at 
keeping losses small.  Otherwise you don't realize the theoretical gain.  This 
means a large radial system.  I use over 100 radials per element.   The 
theoretical gain of my system is about 4 dB.  This is about what I see in 
practice comparing my 2-element array to a single reference vertical.  My array 
is optimized for the low end of the 80m CW band and I get up to 25 dB F/B.  I 
still see some F/B as high as 3700 kHz but by 3800 kHz it is omnidirectional.  
The SWR is close to 1:1 at 3500 kHz but goes up to 2:1 around 3550 kHz.

I use a separate network optimized for 3800 kHz for SSB, but 98% of my 
operation is CW.

The system does work very well provided you have a good ground system.  I have 
worked 333 countries on 80m with this system from an average suburban location.

I also retune this system for 160m operation, but that is another story.

73, John W1FV

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Kees Nijdam
Sent: Tuesday, April 19, 2016 12:07 PM
To: Filipe Lopes; topband
Subject: Re: Topband: 2 element vertical for 80m with 1/8wavelength spacing

Hello Filipe,

Yes, I have such a system.
Cost me several days to optimize it.
My comments.
The 2x157 and 39 degrees phasing lines are based on very good earth systems
(2-3 Ohm). When your radial network is 5 Ohms, it is a different story. That is 
because the driving impedances are very low (in my case 19,27+j21,14 Ohms and 
13,86-j15,73 Ohms) and the influence of the earth system on these impedances is 
big (a 1/4 lambda system is not that critical) If you do not know the 
impedances of your verticals, the only way to go forward is to measure the self 
impedances and the coupled impedances. After that you can follow the calc 
ulations in ON4UN's book and software.

My system is optimized for 3510 kHz and with a signal source at 400 meters I 
found a front to back ratio of 24 dB for this frequency.
On 3500/3520 kHz is was  20 dB, on 3540 kHz only 10 dB and higher in frequency  
the antenna becomes more and more omni directional.
However, the swr was OK over the whole band, also on 3800 kHz.
So it can be used on 3800 kHz but without directivity.

You need a very good radial system and to decide for CW or SSB . My advice: 
better and less critical is to increase the distance between the verticals with 
a few meters.

Is it worth the effort? Yes I think so. I have one vertical permanent and 
during the winter I install the other. The few dB extra gain is good but I was 
also very happy with the system as RX antenna. I have it oriented north-south 
and it is nice to hear KH6AT over the south pole and not over the north pole..

Kees, PE5T

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Re: Topband: Activity today

[Carl Braun]

T32CO and Eugene RA0FF were both booming in this morning here in San Diego.  
Nice to see the activity from these guys.

Carl AG6X

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of David Raymond
Sent: Monday, March 14, 2016 10:10 AM
To: TopBand
Subject: Topband: Activity today

Topbanders. . . while the band has seemed to be in the doldrums there was some 
nice activity on the band today.  5J0P and T32CO were QRV.  They seemed to be 
hearing well as I was able to work them both with 100 watts.  However, the big 
surprise of the morning to finding Eugene, RA0FF, CQing with a 559 signal with 
no takers.  He answered my call running a KW immediately.  He peaked an honest 
S6 near my SR.  Robert, DU7ET, was also QRV as was Ross, 9M2AX.  Both were too 
weak to call but partially copyable for moments.  Cocos-Keeling and Heard will 
both be big challenges from here in Iowa. 

73. . .Dave, W0FLS

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Re: Topband: What have I done?

[Carl Braun]

Thanks for the response and the calculations Don. Lots of offline responses to 
my query.

The antennas use 90 radials 40' to 150' with the average at 66'

Your option B is the way I configured the L network and your numbers are very 
close to mine.

The second variable cap was set aside to use the smaller one.

I'm going to try and roll my own inductor and apply a 70pF cap to gnd or 
variable cap to resonate

Wish me luck

Thanks

Carl AG6X

Sent from my iPhone

On Feb 14, 2016, at 11:56 PM, "Don Kirk" 
<wd8...@gmail.com<mailto:wd8...@gmail.com>> wrote:

Hi Carl,

Does not appear anyone has answered you, so let me give it a quick shot while 
between flights in Japan.  I'm somewhat confused with your final L network 
configuration because you mentioned one capacitor, and then a second capacitor 
without mentioning if you still had the first capacitor in your configuration, 
etc.  You also did not mention what L network configuration you used (see 
below).

Therefore I started from scratch to see what a 64 foot vertical wire would look 
like at 7.050 Mhz to see what kind of L network would be required to convert 
its impedance to a pure 50 ohms resistance.

Using EZNEC demo, I approximate a 64 foot vertical wire on 7.050 Mhz has an 
input impedance of approximately 1274 +j1436 ohms when just using a ground rod 
with medium soil (because this antenna has such a high input impedance it 
really does not matter what I use for ground conductivity).

Then using an online L network calculator I come up with the following two 
different L network configurations you could use to match to a 50 ohm resistive 
source.

L network with inductor between bottom of 64 foot vertical and ground.
L = 10.18 uh
C = 59.9 pf

L network with capacitor between bottom of 64 foot vertical and ground.
L = 8.5 uh
C = 67.6 pf

Not sure what L network configuration you used, but does it sound like I 
closely replicated what you have based upon one of the above mentioned L 
network configurations?  If not, then please better describe your configuration.

Please advise so we can better answer your question, and hopefully I have not 
messed something up with my quick analysis/approximation.

Don (wd8dsb)




On Sat, Feb 13, 2016 at 4:53 PM, Carl Braun 
<carl.br...@lairdtech.com<mailto:carl.br...@lairdtech.com>> wrote:
I have revised my question to correct the length of the antenna in question


Topbanders

In the past, I've posted some questions related to making my 80 meter verticals 
(64' tall ground mounted) work on different bands.  The pair is spaced at ¼ wl 
on 80m and then I switch in base loading to resonate the same pair on 160m 
which are then effectively spaced at 1/8 wl.   Now I want to make them work on 
40m which would have them resonate as ½ or 5/8 wl and would have an effective 
spacing at ½ wl.

So this is what I did...I installed an L network off of the vertical 
effectively tuning a 64' stick of aluminum to 7.050.  It took me a couple of 
tries as the first 1500pF (monster) variable capacitor wouldn't get down low 
enough to get me flat.  I had another 50-150pF Johnson variable cap available 
so I tried that and got the antenna to tune to 46 ohms at j+0.Inside the 
shack I see 1.0:1 Vswr from 7.000 to 7.290...wow!

I measured the cap and it came to 70pf.  My cheapie Chinese meter doesn't 
register anything on the L scale but I have 7 turns on a 3 ½" inductor. The 
full coil is 33 uH at 25 turns so I estimate 8-12 uH of inductance.

But what have I done? Have I resonated a ½ wl antenna or have I resonated 
something else like a 5/8 wl antenna with the added inductance?

I plan on treating them as ½ wl spaced phased verticals on 40 and feeding them 
with equal lengths of ¾ wl feedlines for broadside phasing and then adding an 
additional 2/4 wl to get my 180 degree shift for end fire.

Please share your comments.

thanks

Carl de AG6X

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Topband: What have I done?

[Carl Braun]

Topbanders

In the past, I've posted some questions related to making my 80 meter verticals 
(64' tall ground mounted) work on different bands.  The pair is spaced at ¼ wl 
on 80m and then I switch in base loading to resonate the same pair on 160m 
which are then effectively spaced at 1/8 wl.   Now I want to make them work on 
40m which would have them resonate as ½ or 5/16 or 3/8 wl and would have an 
effective spacing at ½ wl.

So this is what I did...I installed an L network off of the vertical 
effectively tuning a 64' stick of aluminum to 7.050.  It took me a couple of 
tries as the first 1500pF (monster) variable capacitor wouldn't get down low 
enough to get me flat.  I had another 50-150pF Johnson variable cap available 
so I tried that and got the antenna to tune to 46 ohms at j+0.Inside the 
shack I see 1.0:1 Vswr from 7.000 to 7.290...wow!

I measured the cap and it came to 70pf.  My cheapie Chinese meter doesn't 
register anything on the L scale but I have 7 turns on a 3 ½" inductor. The 
full coil is 33 uH at 25 turns so I estimate 8-12 uH of inductance.

But what have I done? Have I resonated a ½ wl antenna or have I resonated 
something else like a 5/16 wl or even a 3/8 wl antenna with the added 
inductance?

I plan on treating them as ½ wl spaced phased verticals on 40 and feeding them 
with equal lengths of ¾ wl feedlines for broadside phasing and then adding an 
additional 2/4 wl to get my 180 degree shift for end fire.

Please share your comments.

thanks

Carl de AG6X

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Re: Topband: What have I done?

[Carl Braun]

I have revised my question to correct the length of the antenna in question


Topbanders

In the past, I've posted some questions related to making my 80 meter verticals 
(64' tall ground mounted) work on different bands.  The pair is spaced at ¼ wl 
on 80m and then I switch in base loading to resonate the same pair on 160m 
which are then effectively spaced at 1/8 wl.   Now I want to make them work on 
40m which would have them resonate as ½ or 5/8 wl and would have an effective 
spacing at ½ wl.

So this is what I did...I installed an L network off of the vertical 
effectively tuning a 64' stick of aluminum to 7.050.  It took me a couple of 
tries as the first 1500pF (monster) variable capacitor wouldn't get down low 
enough to get me flat.  I had another 50-150pF Johnson variable cap available 
so I tried that and got the antenna to tune to 46 ohms at j+0.Inside the 
shack I see 1.0:1 Vswr from 7.000 to 7.290...wow!

I measured the cap and it came to 70pf.  My cheapie Chinese meter doesn't 
register anything on the L scale but I have 7 turns on a 3 ½" inductor. The 
full coil is 33 uH at 25 turns so I estimate 8-12 uH of inductance.

But what have I done? Have I resonated a ½ wl antenna or have I resonated 
something else like a 5/8 wl antenna with the added inductance?

I plan on treating them as ½ wl spaced phased verticals on 40 and feeding them 
with equal lengths of ¾ wl feedlines for broadside phasing and then adding an 
additional 2/4 wl to get my 180 degree shift for end fire.

Please share your comments.

thanks

Carl de AG6X

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Re: Topband: Topband Strange Propagation

[Carl Braun]

Don't the new auto tune amps have the ability to retune with a single dit?

My old Henry takes a lot more than a dit when retuning from 80 to 160. Hi

Carl AG6X

Sent from my iPhone

> On Jan 17, 2016, at 4:37 AM, "Kenneth Grimm"  wrote:
> 
> My take on it was that "the dit marks the spot" either for a buddy or just
> as a "public service."  While not as annoying as other forms of
> transmissions on the DX freq, it still shows bad manners...however, not as
> bad as when I forget to engage the split button.  Maybe that is why I've
> never been nominated for the A1 op award.  At least it's why I wouldn't
> nominate me.
> 
> 73,
> 
> Ken - K4XL
> 
> On Sun, Jan 17, 2016 at 12:31 AM, Louis Parascondola via Topband <
> topband@contesting.com> wrote:
> 
>> I have experienced this single dit when working split on a DX station.  I
>> wondered if it was some kind of malicious interference of some sort but
>> other than what Gary suggested I don't see how it is terribly annoying to
>> the point that one would be making any statement by doing it.
>> 
>> 
>> W1QJ
>> 
>> 
>> 
>> -Original Message-
>> From: Richard (Rick) Karlquist 
>> To: Gary ; topband 
>> Sent: Sat, Jan 16, 2016 11:07 pm
>> Subject: Re: Topband: Topband Strange Propagation
>> 
>> 
>> 
>>> On 1/16/2016 12:10 AM, Gary Smith wrote:
>>> 
>>> There's an odd behavior that we've all heard & that's the "ditter",
>>> the person who on the DX frequency sends the occasional dit, not a
>>> string, just a dit & then some odd seconds later does it again. I
>>> wonder if they do it to bust the chops of someone like me who tries
>> 
>>> KA1J
>> 
>> Some auto tune linears are set up to change bands or sub-bands
>> by sending one dit.  With peak reading meters, they will also
>> display RF out and SWR from one dit.  At least this is a lot
>> less QRM than tuning up the old fashioned way.  In both
>> cases, the solution is to select SPLIT before transmitting
>> or just tuning.
>> 
>> Most rigs have IF gain this is optimized for phone, which
>> means it is way too low for CW.  This results in an AGC
>> threshold that is way above the rig's internal noise level.
>> 
>> Short of redesigning the rig (I actually did this to an FT-757
>> by adding an IF gain stage), you should use an audio attenuator
>> in front of your headphones so the the rig's audio output stage
>> clips before the level in 'phones gets too high.
>> 
>> Rick N6RK
>> _
>> Topband Reflector Archives - http://www.contesting.com/_topband
>> 
>> _
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> 
> 
> 
> -- 
> Ken - K4XL
> BoatAnchor Manual Archive
> BAMA - http://bama.edebris.com
> 
> "Show me a politician who is poor, and I'll show you a poor
> politician." - Carlos
> Hank González
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Re: Topband: Palmyra cursed paradise (K5P)

[Carl Braun]

Thanks Doug. 

Awesome read. Has me wondering about our guys on the island. 

Maybe the "darkness" of the island has something to do with the S9+ signals 
we're seeing here in San Diego. Hi. 

Carl AG6X

Sent from my iPhone

> On Jan 16, 2016, at 1:26 PM, "Doug Turnbull"  wrote:
> 
> Dear OMs and Yls,
> The following link was posted me by Don EI6IL and tells a very
> interesting story of woe and murder on Palmyra Island going back to the very
> discovery of the atoll.Slightly off topic but many of us have illusions
> of working K5P so this may be of interest and also add a bit of spice.   The
> cursed paradise is a good read:
> 
> http://mysteriousuniverse.org/2014/07/the-cursed-paradise-of-palmyra-atoll/
> 
> 
>  Yes EU feels the W6 pain this time and the poor cousins of EI in DL
> and I lands are even worse off than in EI for K5P.   At least the EI path is
> over ocean and tundra rather than thousands of fellow hams.
> 
>   Good hunting.
> 73 Doug EI2CN
> 
> 
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Topband: K5P signal strength

[Carl Braun]

At 1040z here in so cal the K5P station went from NIL to 599 on Topband.  Maybe 
someone found the ON button for the amp?

Carl AG6X
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Re: Topband: K5P signal strength

[Carl Braun]

K5P announced QRX at 1513...20 minutes after my local SR.  Very stron when QRX 
and being reported by other west coast stations.

Now at 1517 still no return with no stations calling.  Maybe a Latte break.

Carl AG6X

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of K4SAV
Sent: Friday, January 15, 2016 7:13 AM
To: topband@contesting.com
Subject: Re: Topband: K5P signal strength

K5P had a big signal around 0900Z this morning.  We had thunderstorms and the 
bands were very noisy but he came in over the top of that.  He faded a little 
later on but still good copy.  I worked him at 0800Z up 1 with no pile to bust. 
 The piles have been large close to sunrise but at 2AM local time it was first 
call, no waiting. He was listening UP during the very early morning hours but a 
little later switched to listening DOWN.

The first day his signal was weak but very persistent.  Copy was OK even though 
he was weak, and I could copy him up to 1 hour after sunrise.  
That's very unusual here.  The piles were huge as you know.

The first day he was on 1826.5 listening UP and working mostly NA but he also 
worked a bunch of JAs.  I was wondering how he did that but now maybe I have a 
clue.

Jerry, K4SAV


On 1/15/2016 8:11 AM, Les Kalmus wrote:
> Apparently, they had problems tuning the Battle Creek Special and were 
> using a SteppIR vertical the first day.
> That's been fixed and was what they were using today.
>
> It's bad enough they were working JA's during this morning's opening 
> but I heard them call EU too and was shaking my head.
>
> Les W2LK
>
>
> On 1/15/2016 7:23 AM, Tim Shoppa wrote:
>> Heard very well here in MD from 1120Z-1220Z on my west-facing 
>> pennant, deep fade at my sunrise to ESP. Working mostly JA's but 
>> trying for NA.
>> (Although
>> at least once K5P called for EU!)
>>
>> Tim N3QE
>>
>> On Fri, Jan 15, 2016 at 5:48 AM, Carl Braun 
>> <carl.br...@lairdtech.com>
>> wrote:
>>
>>> At 1040z here in so cal the K5P station went from NIL to 599 on 
>>> Topband.
>>> Maybe someone found the ON button for the amp?
>>>
>>> Carl AG6X
>>> _
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Re: Topband: RFI - 1825.5

[Carl Braun]

Tony

I have similar birdies on 160 but my worst one resides at the bottom of the 75m 
DX window at 3790 or so.  It's 5kc wide and sounds like a digital warbler. Some 
say its a neighbors noisy router that peaks at S9 when I switch to the 
southwest. 

My nice neighbor lady with the megawatt solar system just informed me that they 
ran a horizontal "electric wire" around the top of their half acre dog pen to 
keep their inbred dogs from launching over the 4' fence. Ugh.   Isn't that the 
same design Marconi used???

I plan on getting my Icom IC91 out with my three element 2m sniffer yagi and 
start walking the streets tomorrow morning. 

Wish me luck

Carl AG6X

Sent from my iPhone

> On Jan 15, 2016, at 3:23 PM, "N2TK, Tony"  wrote:
> 
> I have a new RFI problem. It starts somewhat before sunset and lasts until
> right after sunrise, 7 days a week.
> 
> It has three frequency peaks - 1817.8, 1825.5, 1828.9 MHZ in the lower part
> of 160M.  The bandwidth of the worst one is from 1.824.5 - 1826.1. It has a
> raspy sound to it. 
> 
> I have the general direction so will be taking a walk with a portable radio
> tuned to 1825.5.
> 
> It does not seem to be an external night light as none come on this early in
> the area that I could find so far.
> 
> Very little signal on the second harmonic 3.651. Similar sounds in the same
> direction but not as strong on 1753, 1760, 1764, 1782, 1871, 1883, 1890,
> 1902, 1948. Don't know if these are related the ones on the low end of 160M.
> 
> 
> 
> 
> Any ideas what may generate RF at these frequencies that can help me to
> shorten my search?
> 
> 
> 
> 73,
> 
> N2TK, Tony
> 
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Re: Topband: Strange propagation

[Carl Braun]

JC hit the nail on the head...lets identify those who are using RHR openly.  My 
preference would be a specific suffix designator that would identify the 
transmitting station and then let's see if anyone wants to work a RHR on the 
air.

I witnessed a local san diego station working RHR last Christmas via a KH6 RHR 
station with the implication he was actually in Hawaii.  Operators asked about 
the WX and operating power with the stateside station playing along as if he 
was truly in Hawaii.  QSOs went on and on without any clarification from the 
stateside operator that signed KH6/x.

My suggestion is to determine a suitable (international) suffix designator for 
RHR stations so we all know who and where the signal is coming from...or NOT.  
Those opposed to that rationale could be those that enjoy the thrill of 
deception rather than an honest QSO.  What other reason could there be for a 
station that wouldn't want to use a suffix designator that clearly identifies 
the fact that their RF origin could literally be from anywhere in the world?

BTW, there hasn't been so many posts related to a single topic 
sincewell, since the first time RHR was discussed on the reflector.  
This topic has so many posts it constipated my netzero account.

Carl AG6X

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of JC
Sent: Thursday, January 14, 2016 5:39 PM
To: 'TopBand'
Subject: Re: Topband: Strange propagation



<>

The issue is what you do and not what you say 

If all this new technology is do good , the HRH users should be proud of is and 
PUBLISH, open publicly and announce proudly . 

""  I am a HRH user!!! ""

However that is far from reality,  the main business drive is privacy. HRH 
warranty nobody will possibly know you are using this fantastic technology.

WHY?? Open the list of users, be proud of it! 

My 100 cents

N4IS
JC



-Original Message-
From: Herbert Schoenbohm 
To: topband 
Sent: Thu, Jan 14, 2016 4:54 pm
Subject: Re: Topband: Strange propagation

Dave,  What will happen then is that the RHR gurus will just jack up the rates 
to take the hams with deepest pockets. Additionally the laws of supply will 
kick in and more RHR station and others will invest in this scheme to put more 
stations on the air.  As this progresses the value of the entire DXCC program 
will diminish. There must be some brakes put on this before is is to late.  The 
other night I was thrilled to have an Italian station calling me on 160 only to 
learn later he was actually on the mainland via an RHR station.  Is this the 
way amateur radio is supposed to trend?


Herb Schoenbohm, KV4FZ

On 1/14/2016 5:28 PM, Dave Blaschke, w5un wrote:
> Look at the situation; There are just a few stateside RHR for rent 
> locations. As more and more "hams" begin to use these sites to work 
> DXpeditions, the queue length to access one of these sites will become 
> hopeless long. JUST A THOUGHT.
>
> Dave, W5UN
>
> On 1/14/2016 6:33 PM, Herbert Schoenbohm wrote:
>> I have lost my amateur station in three major hurricanes over the 
>> years here, everything including radios (from water) and antennas. I 
>> have also rebuilt them a four different locations until I finally 
>> scrapped enough money together and bought a home next to a large salt 
>> pond. I have full remote station here but it only functions for 
>> contest operated by a cliff dweller in NYC who cares not for DXCC 
>> credit.  The problem with the US RHR deals is that it completely 
>> skews the process as far as the propagation differences across the 
>> fruited plan.  I would love to add to my DXCC totals as I close into 
>> the 300 mark.  USA stations can do this but is it ethical.  It sure 
>> makes money for a pay to play amateur radio scheme. But is it the way 
>> you want low band Dx-ing to become?  I hope not as you only will need 
>> a computer and an internet connection and everything else that used 
>> to a worthwhile effort is trashed.
>>
>> I remember a former 160 meter DX pioneer, Charles O'Brien who 
>> originally from Illinois used a 1/4 wave bent Marconi and 25 watts to 
>> work a G station.  This is what we are or what we used to be. RHR I 
>> am afraid is the end of an era were perseverance and not vast amounts 
>> of  QRO muscle and money decided who was on top. That is a shame and 
>> perhaps to some a disgrace as it really chances everything including 
>> the respect we have for those who did so much with so little.`
>>
>> Herb Schoenbohm, KV4FZ
>>
>> On 1/14/2016 12:43 AM, Dave Blaschke, w5un wrote:
>>> I will say this:
>>> operating a remote station (for money) owned and managed by someone 
>>> else will never be as satisfying as operating your own station, 
>>> built by your hands. But than again, if you have no station, and are 
>>> unable to build one up, what's your choice? I built (and rebuilt) a 
>>> beautiful station and antenna system here 

Re: Topband: K5P first night

[Carl Braun]

Herb and Topbanders

I, too, heard K5P on TB well after my sunrise here in San Diego...about 25 
minutes past SR.  In fact, the K5P signal on TB was better than it was on 80M.  
I witnessed some real QSB fades on 80 and saw none of that on 160. The pile up 
on 80 was also much less organized than it was on 160...token jammers and such.

FYI, on 80 I use two phased 65' verticals and 1/4 wl spacing with a comtek box 
which was phased SW at Palmyra...I use those same two verticals (in phase 
currently) with base loading for 160...basically an OMNI on 160.  I'll change 
my phasing tonight that allows me to phase wither SW or NE and usually gets me 
a db or two toward the direction of interest.  Maybe tomorrow I can offer an 
update on the signals out of K5P vs SR times for the group.

Let's all support the guys who are making the K5P DXpedition a 
success...especially for us TBers.

Regards 

Carl AG6X

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Herbert 
Schoenbohm
Sent: Thursday, January 14, 2016 12:36 PM
To: Mike Waters; TopBand List
Subject: Re: Topband: K5P first night

First night I heard K5P fine one a nice post S/R peak on TB 45 minutes after my 
SR.  Unfortunately the wall from the mainland was non-penetrable. I noticed 
from the prop chart that the operation doesn't see the wonderful opening I an 
other Caribbean stations would have from
9:00 to 10:00.  Even on 80 CW the ops did a great job an hour or so past my 
S/R.  I know they are concentrating on N/A and I shouldn't try to nudge them on 
an hour earlier.  But this is the constant dilemma with Pacific DX-peditions 
who watch the Sunrise-sunset charts as the boss.  I will also try the EU only 
attempts at their Sunset but the Euros have an even more difficult problem of 
only a few minute window at best.  If only they could stay on after the EU path 
is closed for a few minutes or in the alternative set the alarm clock and get 
one of the top band gurus to light up the path and forget those darn computer 
generate SR/SS charts for just a moment it would be great.

I am going again to the donation page to help a bit with the awesome expenses 
and put some money where my mouth is.


Herb Schoenbohm, KV4FZ

On 1/14/2016 4:08 PM, Mike Waters wrote:
> Never mind. I just found a web site that said "Palmyra *Atoll*".
> https://en.wikipedia.org/wiki/Palmyra_Atoll
> All I have to do now is find your 160m  operating schedule, which so far
> escapes my searches and browsing.
>
> 73, Mike
> www.w0btu.com
>
> On Thu, Jan 14, 2016 at 1:46 PM, Mike Waters  wrote:
>
>> Milt, are you on a DXpedition operating from Palmyra in Syria?! Of all the
>> places!
>>
>> I should switch my antenna back to 160m and see if we can work you.
>>
>>
> _
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Re: Topband: placement oc coil

[Carl Braun]

Hello John

I, too, have experimented with base and top loading with verticals on Topband.  
No question about it, the toploading is much better.  Just take a look at your 
feedpoint impedance with the base coil vs any sort of top loading.  

One point to note, a specific coil that will resonate the base will not provide 
the same loading if placed at the top...more "coil" will be needed if mounted 
near the top of the antenna.

When I had a single 65' vertical with 90 radials resonated with T wire loading 
I had a base impedance near 25 ohms...the same 65' vertical with a large EF 
Johnson broadcast coil at the base gives me close to 10 ohms...ugh!  I use the 
base loading as it provides a cleaner installation vs. overhead loading wires 
but if I had my druthers they would be top loaded with an 80M trap and "L" wire 
to resonate on 160.  

Top load if you can and let us know your results

73 de AG6X

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of 
w5...@towerfarm.net
Sent: Friday, January 08, 2016 3:10 PM
To: topband@contesting.com
Subject: Topband: placement oc coil

Hello to all.I am planning a 60 foot vertical.I am wanting to either place a 
coil on the vertical for topband.The vertical is a hy-tower.I have base 
loaded(not very effective) I have toploaded with a single wire(not enough 
room).I now have plenty of room.So my question.
Base load with many radials,60+
top load at the highest with wires?
top load with coil? and if this is best where should the coil be placed.

thanks to all es 73 john w5jmw
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Topband: Detuning a nearby Tower

[Carl Braun]

Hello Topbanders

I have a two element array 1/8wl away from my 90' Skyneedle tower with Telrex 
yagi atop.  I want to electrically isolate this tower from the array by 
dropping a shunt wire from near the top of the tower down to the panel where I 
have an MFJ model 931 artificial ground (input) that then connects to my earth 
ground.  Tuning the 931 to eliminate the RF field strength induced from the 
array results in an invisible tower to the array...in theory.

In the past, I have used a similar method to shunt feed the tower on 160 ala 
vacuum variable tuning and radials.  When I tapped the tower I found a sweet 
spot at the ~70' level on the skyneedle that provided a fairly good 42 ohm 
match and, once tuned, it worked pretty well on TX.

Here is the concern...I would prefer to use this same tap point for my detuning 
experiment as it seems to make sense that the same point would induce the max 
coupling from the array...or at least be a good starting point.  ON4UN and 
others have implied that, when detuning a tower, you should tap it at the TOP 
of the tower structure and not ¼ of the way down from the top like I's 
considering.

Should I just run the 3' gamma arm off of the very TOP of the tower at the 90' 
level then down or am I better off tapping the gamma arm at the 67' level as I 
did when I shunt fed the tower for TX on 160?

Comments?

Carl

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Re: Topband: 1/2 wl verticals and spaving

[Carl Braun]

Rick

Thanks for the reply.  

I'm glad to hear that it's that simple.  I used the same principle when the 
verticals were dedicated to 40M and were 1/4wl tall where I fed them with 3/4wl 
and 5/4wl coaxial runs.  The gain and side nulls were impressive.

I will invest in some coax and let you know how things develop.

Thanks again

Carl AG6X

-Original Message-
From: Richard (Rick) Karlquist [mailto:rich...@karlquist.com] 
Sent: Sunday, November 29, 2015 11:02 AM
To: Carl Braun; topband@contesting.com
Subject: Re: Topband: 1/2 wl verticals and spaving

On 11/28/2015 6:23 AM, Carl Braun wrote:

> Any suggestions or websites available on ½ wl spacing and ½ wl radiators?
>
> Carl AG6X
>

I did some modeling of this a long time ago.  Basically, the issue is that if 
you feed the 1/2 wave verticals at the base, you need to have a *voltage* 
forcing feed, rather than the usual current forcing feed used for 1/4 wave 
verticals.
This is tough to do if you need a 90 degree phase shift as in a 4 square.  
However, you are in luck because you only need a 0 degree or 180 degree phase 
shift.  As long as your array is physically symmetrical, any symmetrical feed 
network will give the right phasing.  I suggest a simple T junction (in coax) 
with 1/2 wave lines to the verticals.
Make one of them 3/2 wave for 180 degree phasing.
The impedance at this point may be too high for an off the shelf transmatch, so 
you might have to roll your own.

Rick N6RK
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Re: Topband: Diversity-capable transceivers

[Carl Braun]

Barry and fellow Topbanders

I used an Icom 7800 for diversity reception and found it to be a wonderful 
performer.  I would listen to my vertical array on 80 while monitoring the same 
signals with my second receiver connected to either a Pixel loop or a rotatable 
80 dipole.  

Now I am back to my trusty FT1000D with dual RX but it doesn't compare to the 
7800 due to the disadvantaged 2nd RX in the 1000D.  The main RX has all filters 
(incl roofing) but the 2nd RX can only do so much as it introduces noise into 
the mix degrading any weak signals combined from the main RX.

I hear a lot of DXers speaking highly of the Yaesu FTDX5000 series of radios.  
The Sherwood reports seem to think they are among the best "knobbed" XCVRs out 
there if you look past the Flex and K3 rig specs.  The 5000 , the Icom 78XX 
series and the 990 all seem to be great for dual diversity however there are 
some real price differentials in the pack.

Carl


-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Chortek, 
Robert L
Sent: Monday, November 30, 2015 5:36 AM
To: Barry N1EU
Cc: topBand List
Subject: Re: Topband: Diversity-capable transceivers

Hello Barry,

I have been using the 990 for over a year and use it daily on the Low Bands.  I 
find it an exceptional performer. The ergonomics are not quite as good as the 
ICOM 7800, but the receiver performance is much better. The capability of the 
radio is at its best on the low bands, if you look at the ARRL and Sherwood 
engineering receiver performance figures.

You can set both receivers to track one another, but the second receiver in the 
990 is from the Kenwood 590, and is a slightly lower performer, but still very 
good. I do not use it on diversity. 

I have absolutely no regrets.

73,Bob AA6VB

Sent from my iPhone

> On Nov 30, 2015, at 5:24 AM, Barry N1EU  wrote:
> 
> A little research reveals that the TS-990S uses a down-converting 
> subreceiver on the low bands.  Can anybody comment on the stereo 
> diversity capability and performance of the TS-990S and generally how 
> it performs on low-band cw?
> 
> Thanks & 73,
> Barry N1EU
> 
>> On Mon, Nov 30, 2015 at 6:05 AM, Barry N1EU  wrote:
>> 
>> I'm not familiar with the Yaesu/Icom/Kenwood offerings.  Other than 
>> the K3/K3S and Orion/RX366, do any of the other knobbed (non-SDR) hf 
>> transceivers offer a down-converting second receiver that can be used 
>> in stereo diversity mode?
>> 
>> Thanks & 73,
>> Barry N1EU
>> _
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Topband: 1/2 wl verticals and spaving

[Carl Braun]

Topbanders

Im currently using a two element vertical array that I'm able to use on both 80 
and 160M by switching in two different feedlines and matching schemes.  The 
system works well using a Comtek switch box on 80 with the verticals spaced at 
¼ wl and the classic Christman method of feeding the verticals on 160 via 157 
deg feedlines and 37 deg delay line.   Using the same vertical elements results 
in 1/8 wl spacing on 160.

On last challenge I want to tackle is using the same verticals on 40M.  The 
elements would then be effectively spaced ½ wl apart and would be ½ wl tall.

I cannot find any patterns or phasing suggestions for this arrangement...only ¼ 
wl radiators.  Can anyone offer any suggestions for feeding an array like this 
on 40M?

In the past I use the same verticals for 40m but they were only 33' tall and I 
fed it in and out of phase using the Christman coaxial delay line technique and 
it worked well...however, my elements are now 65' tall and all the math surely 
changes.

Any suggestions or websites available on ½ wl spacing and ½ wl radiators?

Thanks

Carl AG6X

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Re: Topband: Control cable black conductors

[Carl Braun]

All

Moisture has gotten to the copper. I've heard white vinegar may work.  Its 
cheap...give it a try

Carl AG6X

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Andy Ikin
Sent: Saturday, February 22, 2014 3:10 AM
To: Dave G4GED; Topband Reflector
Subject: Re: Topband: Control cable black conductors

Dave G4GED Wrote on Feb. 22nd.


Hi and thanks for reading.

I'm trying to splice a damaged (rodents) RX ant control cable.
It has 7 insulated, stranded copper conductors all inside a PVC jacket.
Problem is, when stripped of their insulation, 3 (black, brown and
green), of the copper conductors have become coated in a black film? So
to effect jointing and soldering, require cleaning.
I've tried IPA 170 and several contact cleaners but none remove it.
So far, only Emery Cloth will do the job but it's very difficult to
clean each strand without breaking some and therefore weakening the joint.
All the other 4 conductors are bright clean copper when stripped.
Could anyone tell me why some insulated copper conductors turn black in
this way and whether there's a better way of cleaning it off.


Dave,  maybe you could try dilute sulphuric acid or lime scale remover 
VIAKAL. The black residue on the copper is probably copper oxide.

If you end up replacing the cable run then use tined copper conductors.

73

Andrew G8LUG






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Re: Topband: Shunt feeding the Skyneedle - new developments

[Carl Braun]

Tom

I assume the system has reactance since the MFJ is reading the X and I'm 
seeing the resulting SWR on the analyzer AND at the rig.

The swr at my given freq as tuned with the variable cap is 1.3:1 or 
less...outside the enclosure the system had 1.0:1 swr readings and X=O over 
what appeared to be a broader bandwidth...even with 42 ohms at the feed point. 

I'm having fun in the contest and the antenna seems to be transmitting well and 
the amp hasn't blown up yet.  I have a very short run of RG58 from the panel to 
my switching network so I'm keeping the amplifier below 500W.

I'm definitely ready to get the RX loop up as listening on the needle is rough.

Thanks Tom

Carl AG6X

-Original Message-
From: Tom W8JI [mailto:w...@w8ji.com] 
Sent: Saturday, February 22, 2014 12:17 AM
To: Carl Braun
Cc: 160
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

The j11 ohms is the best I can get period. I was able to get j0 when the cap 
was outside of the steel enclosure with a better bandwidth. Maybe I should 
throw my $400 enclosure and find a fibergla$$ enclosure. But as others have 
indicated I should probably just live with it.

1.) How do you know the system really has some reactance?

2.) What is the SWR, that is more accurate.

3.) The SWR is meaningless anyway for control settings when  it is below 
maybe 1.3, and is typically meaningless for system losses when below 4.0:1 
for short cables on 160 meters. A 40 j10 load (if it is that) is around 
1.3:1, so it falls in the meaningless category


Do you think a smaller (physically) vacuum cap would have less interaction 
with the steel enclosure.  The one I have is only 3 round and 6 long. The 
air variable I'm using is 13 long and 7 round at mesh

RF behavior with chassis and cabinets and wiring can be complicated. Some 
people who work around it all their life never actually get a feel for how 
simple systems work, let alone things that might get colex like high 
impedance lines and physically large components inside close spaced boxes.

The interaction depends on the circuit impedance and the impedance of any 
components and wiring at various points in the system inside the box. You'll 
probably never get a meaningful answer because the problem is small, an 
answer requires knowing the actual impedances of everything, and at a 
minimum a feel for how the box and wiring *you* have interacts with the 
impedances.

The important thing at this point is how the equipment in the shack behaves 
with what you have, because any actual losses are meaningless.

73 Tom 

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Re: Topband: Shunt feeding the Skyneedle - new developments

[Carl Braun]

Charlie

Thanks for the tip.  I may play with a bit of inductance just to see how the 
system reacts. 

Not sure if I can post a pic here but I'm including a shot of the panel and the 
cap...hope you all can see it.  The static bleed choke has been removed and I'm 
awaiting PL 259 connectors from my friends at RF parts.


My crazy dog gets pretty loopy when we play with the Frisbee so I'm considering 
a trial cut in the asphalt to see how easy or ugly the process is.  I hear the 
secret is all in the blade that's used. You Tube has some videos showing the 
procedure for cutting asphalt...we'll see.

Thanks again

Carl AG6X

-Original Message-
From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com] 
Sent: Friday, February 21, 2014 8:18 PM
To: Carl Braun; 'ZR'; '160'
Subject: RE: Topband: Shunt feeding the Skyneedle - new developments

Hi, Carl

Well, I think that what you are doing with your radials should be OK. I
guess I'd rather get them under the asphalt if  I could where they wouldn't
get torn up or b a trip hazard.

BTW I I was playing with your match on the Smith Chart and if you'll add
about 1 uHy inductance in series with the connector (SO-239?) where  you
feedline leaves the enclosure, that will take you to 45 +j0, but I'd be
concerned about incurring more losses in the inductor than any tiny mismatch
loss from the -j11 term. I probably wouldn't do it.

73,
Charlie, K4OTV


-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl
Braun
Sent: Friday, February 21, 2014 10:56 PM
To: Charlie Cunningham; 'ZR'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

I'm working on the radial field weekly.  

Here is a theoretical question that results from my particular QTH.  The
Skyneedle is situated near a secondary blacktop driveway that is in the back
of my property.  I have to run radials over the blacktop to the rest of the
property and, in order to keep things kind of neat, I'm using
multi-conductor rotor cable as radials that travel over the blacktop.  I
have both 6 conductor and 3 conductor control cable that I'm using.  I strip
back the jacket at the radial ring...fan out the wires 3 apart and attach
them to the 1 1/2 copper pipe I'm using as a radial ring around the base of
the 'Needle'.  Then the radial wires converge back into the cable jacket
then travel across the 10' blacktop driveway and then they are removed from
the cable jacket where they fan out into the dirt and are buried.  Most of
these radial wires are 60' to 100' once they leave the jacket.

Any problem with what I'm doing here?  I understand that it would be better
if they fanned out directly from the base but I can have 50+ wires traveling
over the blacktop.

I was even considering getting an asphalt blade and cutting some channels
into the blacktop...burying the jacketed cable into the asphalt and then
sealing then in so I'm not running over them or tripping over them when
playing Frisbee with the hound.

My Guatemalan yard worker has been burying radial wires for the last month
and thinks that I'm LOCO but he likes getting paid at the end of the day.

As we speak I have a total of 34 radials with the shortest being 30' with
the longest at 100'.  Most of them are 60-70'.  Four of them are tied into
my 40m phased array radial field comprised of 90-100 radials under each
antenna ranging from 40' to 80'.  I can change the height of these verticals
from 33' for 40m to 66' for 80m.  1/2 wl spacing on 40 and 1/4 wl spacing on
80.

Carl AG6X

-Original Message-
From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com]
Sent: Friday, February 21, 2014 7:36 PM
To: 'ZR'; Carl Braun; '160'
Subject: RE: Topband: Shunt feeding the Skyneedle - new developments

Well, if I recall correctly, Carl, Carl said his  feedline was about 70' of
LMR-400, so even at 2 2:1 or 2.5:1 VSWR, the excess losses in 70' of LMR-400
at 1.8 MHz are almost 0, so if he can match it OK at the transmitter end of
the line- no real point in making heroic efforts to achieve a perfect
match!  He'd gain more by working on his radial field, and he really should
do that before doing any more tuning because improving the radials WILL
affect the antenna impedance.

73,
Charlie, K4OTV

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of ZR
Sent: Friday, February 21, 2014 10:11 PM
To: Charlie Cunningham; 'Carl Braun'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

The only benefit of getting it better would be a bit more 2:1 VSWR bandwidth
to keep the amp happy but even then there is sometimes a gotcha when tuning
an antenna.

Carl
KM1H



Subject: Re: Topband: Shunt feeding the Skyneedle - new developments


Well, you can do all that, Carl

But if your series variable capacitor is not maxed out (fully meshed) if you
can increase the capacitance enough  to get to j0, you would be at 45
+j0 and on a 1.1:1  VSWR circle

Re: Topband: Shunt feeding the Skyneedle - new developments

[Carl Braun]

The measurements are being taken, and have been taken, at the same point since 
the beginning of the antenna experiment.  The ONLY difference is that the 
variable cap is now mounted inside the steel panel as described in my previous 
posts, instead of outside the panel, as described in previous posts.  Same 
length of wire each scenario. 

I believe Tom W8JI called it when he stated that a change was likely when the 
cap is enclosed in a metallic enclosure vs sitting on a 5 gal plastic jug. 

The Henry amp seems to be OK with a little reactance so I'm going to 
concentrate on my gamma cage and radial system while waiting for RF Parts to 
deliver some necessary connectors. Once I get the PL259s installed I can 
replace my temp RG 58 jumper with the good stuff and then hit it with the 
Henry. Ive kept the power below 500w during the contest so as not to stress the 
small coaxial cable. 

73

Carl

Sent from my iPhone

 On Feb 22, 2014, at 8:42 AM, Carl k...@jeremy.mv.com wrote:
 
 I suppose I missed that part while doing things around here but this is the 
 only pertinent info I can find from him. Nowhere does it say he has a 1:1 
 anywhere with the cap in the cabinet.  Granted some of the posts are very 
 confusing as to where things are being measured.
 
 
 --
 The j11 ohms is the best I can get period. I was able to get j0 when the cap 
 was outside of the steel enclosure with a better bandwidth. Maybe I should 
 throw my $400 enclosure and find a fibergla$$ enclosure. But as others have 
 indicated I should probably just live with it.
 
 The swr at my given freq as tuned with the variable cap is 1.3:1 or 
 less...outside the enclosure the system had 1.0:1 swr readings and X=O over 
 what appeared to be a broader bandwidth...even with 42 ohms at the feed point.
 -- 
 So maybe you can explain where the 1.0 at the transmitter end with the cap in 
 the box came from?
 Additionally the VSWR may/will change with added radials and ground moisture 
 conditions.
 
 Im going out for several hours so no rush on the answers.
 
 Carl
 KM1H
 
 
 - Original Message - From: Charlie Cunningham 
 charlie-cunning...@nc.rr.com
 To: 'Carl' k...@jeremy.mv.com; 'Carl Braun' carl.br...@lairdtech.com; 
 '160' topband@contesting.com
 Sent: Saturday, February 22, 2014 11:03 AM
 Subject: RE: Topband: Shunt feeding the Skyneedle - new developments
 
 
 Well, I agree with all that, Carl. But Carl Braun, was reading dead-flat
 1:1 at the transmitter end of his cable. I believe he is done!! The antenna
 Q is what it is! As for improving his 2:1 VSWR bandwidth he could reduce
 his radial field and increase his ground losses to improve his 2:1 BW -
 but I believe that to be self-defeating!! I'm not missing your point - I
 just don't see what you'd change to improve on a flat line! Carl is well
 past the point of diminishing returns!
 
 The math doesn't lie!
 
 Charlie, K4OTV
 
 
 -Original Message-
 From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl
 Sent: Saturday, February 22, 2014 10:41 AM
 To: Charlie Cunningham; 'Carl Braun'; '160'
 Subject: Re: Topband: Shunt feeding the Skyneedle - new developments
 
 Charlie youre continually missing the point; ignore cable loss period.
 
 The only issue is what impedance does the amp see from lets say 1800 to 1900
 
 KHz? AND can the amp load into it without a problem at full power? This is a
 
 system issue, not just what is measured at the antenna and needs to be
 addressed that way.
 
 Put all that info into your program and post the results. Saying that a 1.3
 VSWR at reasonance at the antenna is sufficient is too simplistic. Compute
 the VSWR at the amp with whatever length of coax is actually used over the
 lower 100 KHz with a range of  at resonance VSWR's.
 
 Carl
 KM1H
 
 
 - Original Message - From: Charlie Cunningham 
 charlie-cunning...@nc.rr.com
 To: 'Carl' k...@jeremy.mv.com; 'Carl Braun'
 carl.br...@lairdtech.com; '160' topband@contesting.com
 Sent: Saturday, February 22, 2014 9:57 AM
 Subject: RE: Topband: Shunt feeding the Skyneedle - new developments
 
 
 Well, Carl the looses in 70' or even 200' of LMR-400 are so low at 1.8 MHz,
 even at 2.0:1 or 3.0 :1, if he can match it at the transmitter  end of the
 line, it really doesn't matter!
 
 Charlie, K4OTV
 
 -Original Message-
 From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl
 Sent: Saturday, February 22, 2014 9:46 AM
 To: Charlie Cunningham; 'Carl Braun'; '160'
 Subject: Re: Topband: Shunt feeding the Skyneedle - new developments
 
 That 1.3 is only at ONE frequency Charlie, he is not crystal controlled.
 What is the 2:1 bandwidth at the amp?
 
 Carl
 KM1H
 
 
 - Original Message - From: Charlie Cunningham 
 charlie-cunning...@nc.rr.com
 To: 'Carl' k...@jeremy.mv.com; 'Carl Braun'
 carl.br...@lairdtech.com; '160' topband

Re: Topband: Shunt feeding the Skyneedle - new developments

[Carl Braun]

Carl and Topbanders

Here are the latest details and I will try and be as thorough as possible.

Good news!  I built my gamma cage and the antenna now performs MUCH better.

Here's where I stand:

90' Tri Ex Skyneedle shunt fed with the gamma arm at 67' and a three wire gamma 
cage with 10 separation between wires.

My tower is grounded at the base via three 1 copper strap 1/8th inch thick and 
tied to a 1 1/2 copper pipe radial ring that measures 4' x 8'. The radial ring 
is also bonded to three 8' ground rods via 1 copper strap.

Currently I have approx 30 ground radials screwed to the radial ring with 
copper clad stainless screws and then painted with copper paste.  Some of the 
radials are formed from heavy control cable (similar to rotor cable) that are 
fanned out at the radial ring...converge into the Cable jacket, cross the 10' 
blacktop driveway and then emerge from the jacket and fan out across the 
property.  The radials vary from 30' long to 100' long with three of them tying 
directly into the radial field of my 40m phased array.

The three-wire gamma cage is made of 14ga stranded wire and converges into a 
cone with a single brass bolt holding all three ring lugs together 1.5' off of 
the ground at the base.  An additional 14ga wire is also connected to the brass 
bolt and bolts to a porcelain feed through insulator that brings the feed into 
the metallic (STEEL) panel.  A 14ga wire then bolts to the other end of the 
feed thru insulator and taps onto the input of the Cardwell air variable 
capacitor.  The output of the capacitor connects to a SO 239 connector that is 
mounted to a 2 copper strap that travels down the enclosure where two brass 
bolts bolt the strap to the bottom of the panel.  Under the panel, where the 
brass bolts emerge from the panel, two 2 copper straps connect to the brass 
bolts and then travel to the copper radial ring where they are terminated. 

Before the gamma cage I used a single 14ga wire dropped down from the gamma arm 
where it connected to the variable cap that was mounted outside my steel 
enclosure and sat on a plastic 5 gal pail.  The gamma wire connected to the 
variable cap and then it was wired to the same standoff insulator I mentioned 
above and into an empty steel panel where I had the same SO 239 connector 
mounted to the copper strap and then to my grounding system.  This config 
netted me 41 + j0 ohms.

I was pretty satisfied with this scenario so I mounted my variable cap on a 
3/4 thick piece of Plexiglas to the backplane via Teflon bolts inside the 
steel enclosure.  When I did this I saw my analyzer jump to 45 -j11 ohms.  No 
matter how much tweaking was done the lowest X on the analyzer was 11.  
Figuring I could live with that after making 24 contacts this morning I decided 
to move ahead with my gamma cage.  When I completed the cage per the info above 
I left my analyzer set on the previous frequency setting of 1825 and saw the 
resistance jump and the X go out of site.  Adjusting my variable cap (from 
approx 140 pf to 420 pf) rewarded me with a 42 + j0 reading.

Inside the shack on the 1000D and the BIRD I see 1.1:1 Vswr at 1.800 MHz, FLAT 
1.0:1 from 1.810 to 1.860 and 1.5:1 at 1.895 MHz.

I'm eager to get back on the air tonight and tomorrow morning to see how it 
plays

73

Carl AG6X



-Original Message-
From: Carl [mailto:k...@jeremy.mv.com] 
Sent: Saturday, February 22, 2014 1:22 PM
To: Carl Braun
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments


Subject: Re: Topband: Shunt feeding the Skyneedle - new developments


The measurements are being taken, and have been taken, at the same point 
since the beginning of the antenna experiment.

**  How about refreshing my merory about those details Carl? Frequency also. 
I wasnt involved in the early parts and deleted them already.


The ONLY difference is that the variable cap is now mounted inside the steel 
panel as described in my previous posts, instead of outside the panel, as 
described in previous posts.  Same length of wire each scenario.

I believe Tom W8JI called it when he stated that a change was likely when 
the cap is enclosed in a metallic enclosure vs sitting on a 5 gal plastic 
jug.

** No discussion needed there, thats been known for 100 years. It would also 
help to be more specific when presenting details, what does metallic really 
mean?

The Henry amp seems to be OK with a little reactance so I'm going to 
concentrate on my gamma cage and radial system while waiting for RF Parts to 
deliver some necessary connectors. Once I get the PL259s installed I can 
replace my temp RG 58 jumper with the good stuff and then hit it with the 
Henry. I've kept the power below 500w during the contest so as not to stress 
the small coaxial cable.

** Good move.

Carl
KM1H


73

Carl

Sent from my iPhone

 On Feb 22, 2014, at 8:42 AM, Carl k...@jeremy.mv.com wrote:

 I suppose I missed that part while doing things around here but this is 
 the only

Topband: Shunt feeding the Skyneedle - new developments

[Carl Braun]

All


Topband list

If you've followed my efforts to shunt feed my Skyneedle tower you'll know that 
I settled with a tap point of 67' and 30 or so of spacing with my feed point 
reading 42 + j0 ohms.  This reading was taken at the interior of my 20 x 30 x 
8 steel Hoffman enclosure with the variable cap located outside the enclosure 
sitting on a plastic 5 gal jug.  The output of the variable cap fed into a 
ceramic feed thru insulator thru the panel to a copper L bracket that mounts 
the SO 239 connector that I hooked my coax cable to.

Since then I've moved the variable capacitor inside the panel and mounted it to 
a ¾ think Plexiglas sheet mounted to the back plane with nylon bolts and 
washers.  There is a 1 air gap between the Plexiglas and the backplane.  I now 
have seen the 42+j0 ohms change to 45 - j11 ohms...that's the lowest reactance 
I can tune the capacitor for. Not really sure if its +j11 ohms or - j11 ohms 
but I assume if the reading was + j11 I could continue to tune it out with the 
capacitor but I cant.

Does the capacitor not play well with a steel enclosure?

The other strange situation I'm experiencing is when I connect my Array 
Solutions static bleed choke to the feed thru insulator at the outside of the 
panel to ground the resonant frequency jumps to 2.014 MHz at 25 +j0 
ohms...remove it entirely and I'm back to my 45 - j11 ohms.

I use 1 meg ohm from the feed point to ground on my other verticals with NO 
change in MFJ analyzer readings.

Any comments from the list on these problems?

Thanks


Carl AG6X

_
Topband Reflector Archives - http://www.contesting.com/_topband

Re: Topband: Shunt feeding the Skyneedle - new developments

[Carl Braun]

Thanks to all who replied

Tom W8JI, your comments on the metallic panel and the static bleed choke make 
sense.  I was so pleased with the FLAT SWR reading with the variable cap 
outside the panel but I guess I can live with the slight SWR.  (Thanks Charlie 
K4OTV).  I have a Nye Viking monster tuner but I hate to use it as my Henry amp 
seems to load strangely when I have it inline so I think I'll just live without 
it.  

Can I add some coax (coiled) to bring the X down on the -j11 reading? I did 
this with the old Telrex and brought the X right down and out of the pic.  I'm 
sure Ill need much more than I would on 14MHz but I think I'd like to try 
anyway.

I'm still going to drop the tower down and add two more gamma wires to create a 
cage and I still have the option of pulling the gamma wire(s) away from the 
tower another 8-10 inches to add a few more ohms to the equation.  

I'm having fun with the experiment.

Right now I'm hearing the beginnings of the SSB contest with N7GP, WD5COV, W6YI 
with the big signals so far.  XE is the only DX I've heard.

Lots of stateside calling stateside

Carl AG6X

-Original Message-
From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com] 
Sent: Friday, February 21, 2014 5:21 PM
To: 'Tom W8JI'; Carl Braun; '160'
Subject: RE: Topband: Shunt feeding the Skyneedle - new developments

Well, Carl

I plotted your 45-j11 load on a Smith Chart (normalized to 50 ohms) and it's
very near the origin on a 1.3:1 VSWR circle. Since you have a relatively
short feedline of LMR-400, You should be able to just tune it out at the
transmitter end of the line, and the LMR-400 line will be operating at such
a very low SWR (around 1.3:1 that the excess loss from a 1.3:1 VSWR at 160
is completely trivial and negligible! It may not be completely
intellectually satisfying to have -j11 of reactance at the load, but it
should match easily and the antenna should work very well!  Enjoy!

Sounds like that Array solutions static bleed is not as high in impedance as
we might wish! A large resistance might give you more satisfactory results!

GL!  Enjoy!

73,
Charlie, K4OTV





-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Tom W8JI
Sent: Friday, February 21, 2014 8:02 PM
To: Carl Braun; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

Since then I've moved the variable capacitor inside the panel and mounted it

to a ¾ think Plexiglas sheet mounted to the back plane with nylon bolts and

washers.  There is a 1 air gap between the Plexiglas and the backplane.  I 
now have seen the 42+j0 ohms change to 45 - j11 ohms...that's the lowest 
reactance I can tune the capacitor for. Not really sure if its +j11 ohms 
or - j11 ohms but I assume if the reading was + j11 I could continue to tune

it out with the capacitor but I cant.

Does the capacitor not play well with a steel enclosure?

Any enclosure will change things, especially a metallic enclosure. Just 
readjust the cap.

The other strange situation I'm experiencing is when I connect my Array 
Solutions static bleed choke to the feed thru insulator at the outside of 
the panel to ground the resonant frequency jumps to 2.014 MHz at 25 +j0 
ohms...remove it entirely and I'm back to my 45 - j11 ohms.

The choke is completely unnecessary with a shunt feed tower. It won't help a

thing, so leave it out.

73 Tom 

_
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Re: Topband: Shunt feeding the Skyneedle - new developments

[Carl Braun]

Charlie

The cap is no where near maxed out.  I'm using approx 150pf of a 1050pf 
variable cap.  

Carl

-Original Message-
From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com] 
Sent: Friday, February 21, 2014 6:37 PM
To: Carl Braun; 'Tom W8JI'; '160'
Subject: RE: Topband: Shunt feeding the Skyneedle - new developments

Well, you can do all that, Carl

But if your series variable capacitor is not maxed out (fully meshed) if
you can increase the capacitance enough  to get to j0, you would be at 45
+j0 and on a 1.1:1  VSWR circle. No point int trying to do better than
that!!
 Otherwise, just increase the series capacitance to bring that -j11  as
close to j0 as possible and take that! You'd be so near perfect that there
would be no real point in going further!

Your time and efforts might be better spent working on  your radial field!

73,
Charlie, K4OTV


-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl
Braun
Sent: Friday, February 21, 2014 8:46 PM
To: Charlie Cunningham; 'Tom W8JI'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

Thanks to all who replied

Tom W8JI, your comments on the metallic panel and the static bleed choke
make sense.  I was so pleased with the FLAT SWR reading with the variable
cap outside the panel but I guess I can live with the slight SWR.  (Thanks
Charlie K4OTV).  I have a Nye Viking monster tuner but I hate to use it as
my Henry amp seems to load strangely when I have it inline so I think I'll
just live without it.  

Can I add some coax (coiled) to bring the X down on the -j11 reading? I did
this with the old Telrex and brought the X right down and out of the pic.
I'm sure Ill need much more than I would on 14MHz but I think I'd like to
try anyway.

I'm still going to drop the tower down and add two more gamma wires to
create a cage and I still have the option of pulling the gamma wire(s) away
from the tower another 8-10 inches to add a few more ohms to the equation.  

I'm having fun with the experiment.

Right now I'm hearing the beginnings of the SSB contest with N7GP, WD5COV,
W6YI with the big signals so far.  XE is the only DX I've heard.

Lots of stateside calling stateside

Carl AG6X

-Original Message-
From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com] 
Sent: Friday, February 21, 2014 5:21 PM
To: 'Tom W8JI'; Carl Braun; '160'
Subject: RE: Topband: Shunt feeding the Skyneedle - new developments

Well, Carl

I plotted your 45-j11 load on a Smith Chart (normalized to 50 ohms) and it's
very near the origin on a 1.3:1 VSWR circle. Since you have a relatively
short feedline of LMR-400, You should be able to just tune it out at the
transmitter end of the line, and the LMR-400 line will be operating at such
a very low SWR (around 1.3:1 that the excess loss from a 1.3:1 VSWR at 160
is completely trivial and negligible! It may not be completely
intellectually satisfying to have -j11 of reactance at the load, but it
should match easily and the antenna should work very well!  Enjoy!

Sounds like that Array solutions static bleed is not as high in impedance as
we might wish! A large resistance might give you more satisfactory results!

GL!  Enjoy!

73,
Charlie, K4OTV





-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Tom W8JI
Sent: Friday, February 21, 2014 8:02 PM
To: Carl Braun; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

Since then I've moved the variable capacitor inside the panel and mounted it

to a ¾ think Plexiglas sheet mounted to the back plane with nylon bolts and

washers.  There is a 1 air gap between the Plexiglas and the backplane.  I 
now have seen the 42+j0 ohms change to 45 - j11 ohms...that's the lowest 
reactance I can tune the capacitor for. Not really sure if its +j11 ohms 
or - j11 ohms but I assume if the reading was + j11 I could continue to tune

it out with the capacitor but I cant.

Does the capacitor not play well with a steel enclosure?

Any enclosure will change things, especially a metallic enclosure. Just 
readjust the cap.

The other strange situation I'm experiencing is when I connect my Array 
Solutions static bleed choke to the feed thru insulator at the outside of 
the panel to ground the resonant frequency jumps to 2.014 MHz at 25 +j0 
ohms...remove it entirely and I'm back to my 45 - j11 ohms.

The choke is completely unnecessary with a shunt feed tower. It won't help a

thing, so leave it out.

73 Tom 

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Re: Topband: Shunt feeding the Skyneedle - new developments

[Carl Braun]

I'm working on the radial field weekly.  

Here is a theoretical question that results from my particular QTH.  The 
Skyneedle is situated near a secondary blacktop driveway that is in the back of 
my property.  I have to run radials over the blacktop to the rest of the 
property and, in order to keep things kind of neat, I'm using multi-conductor 
rotor cable as radials that travel over the blacktop.  I have both 6 conductor 
and 3 conductor control cable that I'm using.  I strip back the jacket at the 
radial ring...fan out the wires 3 apart and attach them to the 1 1/2 copper 
pipe I'm using as a radial ring around the base of the 'Needle'.  Then the 
radial wires converge back into the cable jacket then travel across the 10' 
blacktop driveway and then they are removed from the cable jacket where they 
fan out into the dirt and are buried.  Most of these radial wires are 60' to 
100' once they leave the jacket.

Any problem with what I'm doing here?  I understand that it would be better if 
they fanned out directly from the base but I can have 50+ wires traveling over 
the blacktop.

I was even considering getting an asphalt blade and cutting some channels into 
the blacktop...burying the jacketed cable into the asphalt and then sealing 
then in so I'm not running over them or tripping over them when playing Frisbee 
with the hound.

My Guatemalan yard worker has been burying radial wires for the last month and 
thinks that I'm LOCO but he likes getting paid at the end of the day.

As we speak I have a total of 34 radials with the shortest being 30' with the 
longest at 100'.  Most of them are 60-70'.  Four of them are tied into my 40m 
phased array radial field comprised of 90-100 radials under each antenna 
ranging from 40' to 80'.  I can change the height of these verticals from 33' 
for 40m to 66' for 80m.  1/2 wl spacing on 40 and 1/4 wl spacing on 80.

Carl AG6X

-Original Message-
From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com] 
Sent: Friday, February 21, 2014 7:36 PM
To: 'ZR'; Carl Braun; '160'
Subject: RE: Topband: Shunt feeding the Skyneedle - new developments

Well, if I recall correctly, Carl, Carl said his  feedline was about 70' of
LMR-400, so even at 2 2:1 or 2.5:1 VSWR, the excess losses in 70' of LMR-400
at 1.8 MHz are almost 0, so if he can match it OK at the transmitter end of
the line- no real point in making heroic efforts to achieve a perfect
match!  He'd gain more by working on his radial field, and he really should
do that before doing any more tuning because improving the radials WILL
affect the antenna impedance.

73,
Charlie, K4OTV

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of ZR
Sent: Friday, February 21, 2014 10:11 PM
To: Charlie Cunningham; 'Carl Braun'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

The only benefit of getting it better would be a bit more 2:1 VSWR bandwidth
to keep the amp happy but even then there is sometimes a gotcha when tuning
an antenna.

Carl
KM1H



Subject: Re: Topband: Shunt feeding the Skyneedle - new developments


Well, you can do all that, Carl

But if your series variable capacitor is not maxed out (fully meshed) if you
can increase the capacitance enough  to get to j0, you would be at 45
+j0 and on a 1.1:1  VSWR circle. No point int trying to do better than
that!!
 Otherwise, just increase the series capacitance to bring that -j11  as
close to j0 as possible and take that! You'd be so near perfect that there
would be no real point in going further!

Your time and efforts might be better spent working on  your radial field!

73,
Charlie, K4OTV


-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl
Braun
Sent: Friday, February 21, 2014 8:46 PM
To: Charlie Cunningham; 'Tom W8JI'; '160'
Subject: Re: Topband: Shunt feeding the Skyneedle - new developments

Thanks to all who replied

Tom W8JI, your comments on the metallic panel and the static bleed choke
make sense.  I was so pleased with the FLAT SWR reading with the variable
cap outside the panel but I guess I can live with the slight SWR.  (Thanks
Charlie K4OTV).  I have a Nye Viking monster tuner but I hate to use it as
my Henry amp seems to load strangely when I have it inline so I think I'll
just live without it.

Can I add some coax (coiled) to bring the X down on the -j11 reading? I did
this with the old Telrex and brought the X right down and out of the pic.
I'm sure Ill need much more than I would on 14MHz but I think I'd like to
try anyway.

I'm still going to drop the tower down and add two more gamma wires to
create a cage and I still have the option of pulling the gamma wire(s) away
from the tower another 8-10 inches to add a few more ohms to the equation.

I'm having fun with the experiment.

Right now I'm hearing the beginnings of the SSB contest with N7GP, WD5COV,
W6YI with the big signals so far.  XE is the only DX I've heard

Re: Topband: Update from AG6X shunt feed project

[Carl Braun]

Thanks Charlie

I haven't transmitted on the antenna yet but I did hear KH6XX, KH6LC and WL7E 
this morning along with a bunch of stateside guys participating in the contest. 

N7GP and K7FA in AZ were +20 this morning and N7XM was loud too. 

I'm looking forward to seeing improvements with additional radials but I do 
anticipate the R dropping too. If things improve too much I may be moving the 
gamma arm up to the 90' level yet.

More later. 

Thanks again 

Carl AG6X

Sent from my iPhone

 On Feb 16, 2014, at 7:37 AM, Charlie Cunningham 
 charlie-cunning...@nc.rr.com wrote:
 
 Wow!, that's perfect, Carl!! That should result in better than 1.2:1 load
 VSWR!!  No wonder you see a flat line at the transmitter end!  Looks like
 either 90' or 67' would be good tap points, but 67' is better!  Can't do
 much better than 42 ohms feed-point resistance!
 
 If you're seeing a flat line from 1800-1850 that's pretty good bandwidth!!
 
 I'm not sure how much you might gain by adding additional gamma wires, The
 loss in 67' of 14 ga wire can't be that great! The impedance of your gamma
 may decrease with the additional wires, requiring a larger capacitor to tune
 it!  There's a lot to be said for  If it ain't broke -don't fix lt!
 
 Regarding the gamma capacitor - if I did my quick back of the envelope
 'rithmatic right, the 140 pf of capacitance should have about 36.2 ohms of
 capacitive reactance at 1.8 MHz. Now, if you are delivering 1500 watts of RF
 into a 42 ohm load, that's a little less than 6 amps RMS of RF current.
 That would result in an RMS voltage of about 220 volts across the 140 pF, or
 about 330 volts peak.  So your 4500 volt Cardwell should have no problems
 dealing with it.  No need to use your vacuum variable! 
 
 If you add additional gamma wires, you  may need something a bit larger than
 your 160 pF capacitor, but the voltage requirements wouldn't increase
 significantly, if at all.  Of course whatever capacitor you use, you, of
 course, need to protect it from moisture, insects etc.
 
 Sounds like you have it working well, and you can concentrate on workin' on
 your radial field. Of course, as you improve the radials, you may see that
 42 ohm resistance drop a little and your BW decrease as you reduce the
 ground losses and the Q of you antenna system increases! I've had that
 experience in the past.
 
 Anyway, Carl, sounds like you  have it playing pretty well!  Have fun!
 
 73,
 Charlie, K4OTV
 
 
 
 
 -Original Message-
 From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl
 Braun
 Sent: Saturday, February 15, 2014 9:03 PM
 To: topband@contesting.com
 Subject: Topband: Update from AG6X shunt feed project
 
 
 All
 
 I decided to take a chance at tapping the tower at 67' and apply some series
 capacitance to see how the structure would work there before tapping it at
 the 90' level.  Here is what I found:
 
 The gamma arm spacing is at 33 and with 140pf in series I see 42+j0 ohms at
 the feedpoint.  Inside the shack at the end of the LMR 400 I see basically
 FLAT SWR from 1800 to 1850 and 1.5:1 at 1865...with the cap fixed at 140pf.
 
 All of that with my skimpy (single 14AWG) gamma wire.
 
 Tomorrow I plan on dropping the tower again to add the additional 2 or 3
 wires to create the gamma wire cage.  My current PVC standoffs have been
 modified to accept three gamma wires spaced approx. 10 apart (though I'm
 only using one now as I said before). I'm assuming this MAY provide me with
 a couple more ohms getting me closer to the magical 50 but bandwidth is what
 I'm truly after.  If I still need a few more ohms I may extend the gamma and
 standoff arms out another 6 or so...which would be the MAX reach without
 installing new arm and standoffs.
 
 So...with these low capacitance requirements (140pf now and possibly less
 with the multiple gamma wires) will I still need to scrounge my vacuum
 variable out of storage or will my 4500V Cardwell cap get the job done at
 1500W?
 
 Thanks to all who offered their advice and look for an update from me after
 the gamma cage is assembled and additional radials are installed
 
 Carl AG6X
 _
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_
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Re: Topband: Still in search of resonance - Detailed Observations and Calculations

[Carl Braun]

Charlie

Thank you for your work and insight.

It appears I've I may have provided some incorrect info.

When I tapped the tower at 90' I used the 160pf variable cap to get down to the 
68 ohm impedance measurement and, yes, it heard well with what appeared to be a 
peak at approx 1770kc   I never transmitted there. I've only transmitted with 
the system when I had a tap at 46' where I saw 24 ohms and X=0 with the 
variable. Ap on series.  Then I installed a 22 to 50 ohm Unun and made the 
contacts to east coast stations.

I believe I have plenty of capacitance on hand if I tap the tower at 90' but 
given the 68 ohm reading at 90' with the variable cap and the 24 ohm reading at 
46' with the variable cap don't you think the best bet would be my 67' tap 
point?  Even if it's still a bit low in resistance at that point i could add a 
bit of parallel C in conjunction with the series C to bring the antenna to 50 
ohms+j0?

Please advise and thank you for the most enjoyable technical conversation.

Carl AG6X
Sent from my iPhone

On Feb 15, 2014, at 9:14 AM, Charlie Cunningham 
charlie-cunning...@nc.rr.commailto:charlie-cunning...@nc.rr.com wrote:

Well, here it is with the re-built loss table, Carl

73,
Charlie, K4OTV

From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com]
Sent: Saturday, February 15, 2014 11:35 AM
To: 'Carl Braun'; '160'
Subject: RE: Topband: Still in search of resonance - Detailed Observations and 
Calculations


Hi, Carl



I did a bit of further investigation and work on your problem.



I think you are done, as follows:



1.0  Just tap the Skyneedle at 90' and tune out the series inductive 
reactance with a variable capacitor, leaving you with 68 ohms real at the 
bottom of your drop wire. Great match! VSWR on 50 ohm feed cable of 
1.4:1.



2.0  Now, let's  assume you have 250 feet of Belden 8237 (RG-8) feeding 
the bottom of the drop wire. Losses are as follows:



Line/Load



Line type:Belden 8237 RG8

Line length  250’

Frequency  1.8 MHz

Load SWR1.4:1

Power In  100W



Results:



Matched Loss:   0.577 dB

SWR Loss 0.029 dB

Total Loss0.606 dB

Power Out  86.982 W






Note that the excess loss due to the SWR on the cable is 0.029 dB, out of a 
total loss in 250’ of RG-8 of 0.606 dB

Note the “flat-loss” or “matched loss” of the cable (at 1:1 VSWR) is 0.577 dB.  
So there’s no real point in struggling to get to exactly 50 ohms real at the 
bottom of your drop-wire to recover 0.029 dB of loss in 250’ of cable!  Your 68 
ohms is just fine! Just match tle line at the transmitter end and accept the 
modest 1.4:1 VSWR at the load end.

As you observed, when tapped at 90’ the tower “heard” very well and you made 
some contacts with your FT-1000D barefoot.

So, it surely appears that you have a very good, well-matched antenna when you 
“tap” at 90’ and tune out the series inductance of the gamma match in the 
normal way using a series capacitor. Just tune for X=0 at th bottom of the drop 
wire, connect the feedline and match the feedline at the transmitter and enjoy!!

Of course, with a tower that tall, you probably want a “spark gap” and/or a 
gas-tube at the feed-point and sopme sortof static bleed to defend agains 
static charge and lightning!

GL!

Have fun!

73.

Charlie, K4OTV









-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Braun
Sent: Friday, February 14, 2014 6:15 PM
To: '160'
Subject: Topband: Still in search of resonance



List



Some of you may have followed my efforts in trying to shunt feed my 90' Tri-Ex 
Skyneedle with 20 meter yagi at 93'.  I'm still unable to find any sort of 
resonance point on the tower.  To refresh everyone's memory here are the 
specifics:



90' Skyneedle that is 12 round at the base and 4 round at the top



13' of mast out the top



5 element Telrex 20M monobander mounted at the 93' level.  No other antennas on 
the tower



1 ½ copper pipe as a radial ring that surrounds the concrete base that 
measures 4' x 8' rectangle.  Three  8' ground rods are connected to the radial 
ring via 1 copper strap that is .125 thick.



Currently I have 27 14AWG insulated wire radials.  Most of the radials are 20' 
to 50' long with three at 90 to 120' long and four of them connected to my 40M 
vertical array which have 100 count radials 50' to 100' each.



The tower is grounded to each ground rod via 1 copper strap .125 thick and, 
as mentioned above, the ground rods are connected to the radial ring with the 
same strap with copper clad stainless screws.



When I bolted the gamma arm to the tower at the 90' height I dropped a single 
14AWG wire to the ground where my FLUKE meter read ZERO ohms between the radial

Re: Topband: Still in search of resonance - Detailed Observations and Calculations

[Carl Braun]

Charlie

FYI. I'm using 60' to 70' of LMR400 from my panel at the base of the needle to 
the shack. No long runs here.

Carl AG6X

Sent from my iPhone

On Feb 15, 2014, at 9:14 AM, Charlie Cunningham 
charlie-cunning...@nc.rr.commailto:charlie-cunning...@nc.rr.com wrote:

Well, here it is with the re-built loss table, Carl

73,
Charlie, K4OTV

From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com]
Sent: Saturday, February 15, 2014 11:35 AM
To: 'Carl Braun'; '160'
Subject: RE: Topband: Still in search of resonance - Detailed Observations and 
Calculations


Hi, Carl



I did a bit of further investigation and work on your problem.



I think you are done, as follows:



1.0  Just tap the Skyneedle at 90' and tune out the series inductive 
reactance with a variable capacitor, leaving you with 68 ohms real at the 
bottom of your drop wire. Great match! VSWR on 50 ohm feed cable of 
1.4:1.



2.0  Now, let's  assume you have 250 feet of Belden 8237 (RG-8) feeding 
the bottom of the drop wire. Losses are as follows:



Line/Load



Line type:Belden 8237 RG8

Line length  250’

Frequency  1.8 MHz

Load SWR1.4:1

Power In  100W



Results:



Matched Loss:   0.577 dB

SWR Loss 0.029 dB

Total Loss0.606 dB

Power Out  86.982 W






Note that the excess loss due to the SWR on the cable is 0.029 dB, out of a 
total loss in 250’ of RG-8 of 0.606 dB

Note the “flat-loss” or “matched loss” of the cable (at 1:1 VSWR) is 0.577 dB.  
So there’s no real point in struggling to get to exactly 50 ohms real at the 
bottom of your drop-wire to recover 0.029 dB of loss in 250’ of cable!  Your 68 
ohms is just fine! Just match tle line at the transmitter end and accept the 
modest 1.4:1 VSWR at the load end.

As you observed, when tapped at 90’ the tower “heard” very well and you made 
some contacts with your FT-1000D barefoot.

So, it surely appears that you have a very good, well-matched antenna when you 
“tap” at 90’ and tune out the series inductance of the gamma match in the 
normal way using a series capacitor. Just tune for X=0 at th bottom of the drop 
wire, connect the feedline and match the feedline at the transmitter and enjoy!!

Of course, with a tower that tall, you probably want a “spark gap” and/or a 
gas-tube at the feed-point and sopme sortof static bleed to defend agains 
static charge and lightning!

GL!

Have fun!

73.

Charlie, K4OTV









-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Braun
Sent: Friday, February 14, 2014 6:15 PM
To: '160'
Subject: Topband: Still in search of resonance



List



Some of you may have followed my efforts in trying to shunt feed my 90' Tri-Ex 
Skyneedle with 20 meter yagi at 93'.  I'm still unable to find any sort of 
resonance point on the tower.  To refresh everyone's memory here are the 
specifics:



90' Skyneedle that is 12 round at the base and 4 round at the top



13' of mast out the top



5 element Telrex 20M monobander mounted at the 93' level.  No other antennas on 
the tower



1 ½ copper pipe as a radial ring that surrounds the concrete base that 
measures 4' x 8' rectangle.  Three  8' ground rods are connected to the radial 
ring via 1 copper strap that is .125 thick.



Currently I have 27 14AWG insulated wire radials.  Most of the radials are 20' 
to 50' long with three at 90 to 120' long and four of them connected to my 40M 
vertical array which have 100 count radials 50' to 100' each.



The tower is grounded to each ground rod via 1 copper strap .125 thick and, 
as mentioned above, the ground rods are connected to the radial ring with the 
same strap with copper clad stainless screws.



When I bolted the gamma arm to the tower at the 90' height I dropped a single 
14AWG wire to the ground where my FLUKE meter read ZERO ohms between the radial 
ring and the end of the gamma wire with no fluctuations so I'm confident that I 
have good continuity throughout the tower.



Here are the readings that I saw on the MFJ analyzer with the gamma arm mounted 
at the (4) points on the tower that are available...



With the gamma arm mounted at 90' and 36 spacing I saw 425 ohms at the end of 
the drop wire on the MFJ



With the gamma arm mounted at 67' and 36 spacing I saw 380 ohms at the end of 
the drop wire on the MFJ



With the gamma arm mounted at 46' and 36 spacing I saw 240 ohms at the end of 
the drop wire on the MFJ



With the gamma arm mounted at 28' and 36 spacing I saw 120 ohms at the end of 
the drop wire on the MFJ



At all of these points I was able to knock down the R with my honkin' 1050pf 
cap to some resonance sort of resonance at 1.825 MHz but, as most everyone has 
indicated, I should be able to find

Re: Topband: Still in search of resonance

[Carl Braun]

Tom

After reading your post yesterday I had a dream that I woke up and saw one of 
those flying monkeys on top of my tower laughing and sawing away.  

Carl AG6X

-Original Message-
From: Tom W8JI [mailto:w...@w8ji.com] 
Sent: Friday, February 14, 2014 6:02 PM
To: Carl Braun; '160'
Subject: Re: Topband: Still in search of resonance

Hi Carl,

It sounds like you are trying to find 50 ohms on the tower without any series 
capacitor by looking at R and X. I would not try to do that. The reactance puts 
you out of range on the MFJ bridge.  You are down to a few bits difference 
between data points the PIC needs in the MFJ.

Look at this below. You said:

seen at the other levels too as long as I brought the R down with a 
variable cap.  Yesterday, with the gamma arm at the 46' level (and 240 ohms on 
the MFJ) I was able to put the big variable inline to bring the reading to 24 
ohms with a TRUE X=0.  With a 22 ohm to 50 ohm UNUN, I saw 1.3:1 Vswr on the 
output of the UNUN.  I worked a W2 in NJ and a W4 in Florida with just the 
1000D.  BUT...again...I'm bringing the R down with the capacitor...not finding 
50 ohms anywhere on the tower

Stop trying to find 50 ohms without the capacitor!

Right now at 46 ft you were at 24 ohms with the capacitor. That should tell 
you and everyone on this reflector :-)   that you are tapped too low now!

Let's look at this in simple terms. Here is what you said:

When I had the gamma arm mounted at the 90' level. I was able to put my 
baby variable 160pf inline to bring the 425 ohm impedance down to about 60 ohms 
and the antenna heard very well; especially on the 1700 KHz broadcast band, 
with a 2.4:1 Vswr.  Similar results could be seen at the other levels too as 
long as I brought the R down with a variable cap. 

That is NORMAL. You will always need the capacitor. Always. The only way to 
eliminate the capacitor is to saw your Yagi antenna off the tower so the tower 
moves above 2 MHz. Then you will probably find a 50j0 tap without any capacitor.

You also might use a large skirt, but why??

Just use a capacitor!!!

If you are trying to eliminate the capacitor, you will have a lot of work to do.

73 Tom 

_
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Topband: Update from AG6X shunt feed project

[Carl Braun]

All

I decided to take a chance at tapping the tower at 67' and apply some series 
capacitance to see how the structure would work there before tapping it at the 
90' level.  Here is what I found:

The gamma arm spacing is at 33 and with 140pf in series I see 42+j0 ohms at 
the feedpoint.  Inside the shack at the end of the LMR 400 I see basically FLAT 
SWR from 1800 to 1850 and 1.5:1 at 1865...with the cap fixed at 140pf.

All of that with my skimpy (single 14AWG) gamma wire.

Tomorrow I plan on dropping the tower again to add the additional 2 or 3 wires 
to create the gamma wire cage.  My current PVC standoffs have been modified to 
accept three gamma wires spaced approx. 10 apart (though I'm only using one 
now as I said before). I'm assuming this MAY provide me with a couple more ohms 
getting me closer to the magical 50 but bandwidth is what I'm truly after.  If 
I still need a few more ohms I may extend the gamma and standoff arms out 
another 6 or so...which would be the MAX reach without installing new arm and 
standoffs.

So...with these low capacitance requirements (140pf now and possibly less with 
the multiple gamma wires) will I still need to scrounge my vacuum variable out 
of storage or will my 4500V Cardwell cap get the job done at 1500W?

Thanks to all who offered their advice and look for an update from me after the 
gamma cage is assembled and additional radials are installed

Carl AG6X
_
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Topband: Still in search of resonance

[Carl Braun]

List

Some of you may have followed my efforts in trying to shunt feed my 90' Tri-Ex 
Skyneedle with 20 meter yagi at 93'.  I'm still unable to find any sort of 
resonance point on the tower.  To refresh everyone's memory here are the 
specifics:

90' Skyneedle that is 12 round at the base and 4 round at the top

13' of mast out the top

5 element Telrex 20M monobander mounted at the 93' level.  No other antennas on 
the tower

1 ½ copper pipe as a radial ring that surrounds the concrete base that 
measures 4' x 8' rectangle.  Three  8' ground rods are connected to the radial 
ring via 1 copper strap that is .125 thick.

Currently I have 27 14AWG insulated wire radials.  Most of the radials are 20' 
to 50' long with three at 90 to 120' long and four of them connected to my 40M 
vertical array which have 100 count radials 50' to 100' each.

The tower is grounded to each ground rod via 1 copper strap .125 thick and, 
as mentioned above, the ground rods are connected to the radial ring with the 
same strap with copper clad stainless screws.

When I bolted the gamma arm to the tower at the 90' height I dropped a single 
14AWG wire to the ground where my FLUKE meter read ZERO ohms between the radial 
ring and the end of the gamma wire with no fluctuations so I'm confident that I 
have good continuity throughout the tower.

Here are the readings that I saw on the MFJ analyzer with the gamma arm mounted 
at the (4) points on the tower that are available...

With the gamma arm mounted at 90' and 36 spacing I saw 425 ohms at the end of 
the drop wire on the MFJ

With the gamma arm mounted at 67' and 36 spacing I saw 380 ohms at the end of 
the drop wire on the MFJ

With the gamma arm mounted at 46' and 36 spacing I saw 240 ohms at the end of 
the drop wire on the MFJ

With the gamma arm mounted at 28' and 36 spacing I saw 120 ohms at the end of 
the drop wire on the MFJ

At all of these points I was able to knock down the R with my honkin' 1050pf 
cap to some resonance sort of resonance at 1.825 MHz but, as most everyone has 
indicated, I should be able to find a 50 ohm tap somewhere on the tower.  I 
can't find it.

When I had the gamma arm mounted at the 90' level. I was able to put my baby 
variable 160pf inline to bring the 425 ohm impedance down to about 60 ohms and 
the antenna heard very well; especially on the 1700 KHz broadcast band, with a 
2.4:1 Vswr.  Similar results could be seen at the other levels too as long as I 
brought the R down with a variable cap.  Yesterday, with the gamma arm at the 
46' level (and 240 ohms on the MFJ) I was able to put the big variable inline 
to bring the reading to 24 ohms with a TRUE X=0.  With a 22 ohm to 50 ohm UNUN, 
I saw 1.3:1 Vswr on the output of the UNUN.  I worked a W2 in NJ and a W4 in 
Florida with just the 1000D.  BUT...again...I'm bringing the R down with the 
capacitor...not finding 50 ohms anywhere on the tower.

Is my radial field so poor that I'm seeing these goofy readings?

Is the single 14AWG too thin causing goofy readings?

I'm back to scratching my head.

Comments from the list?



Carl AG6X

_
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Re: Topband: Still in search of resonance

[Carl Braun]

Thanks Dean

The one I'm looking at is the old heathkit with the various coil plug ins. The 
kit comes with a coil that goes down to 1.600. 

Is there another one you can recommend that may go down further?  ON4UN says my 
tower should be close to 115 degrees others say closer to 140 degrees 

Thanks for your input. I agree with you wholeheartedly. 

Carl AG6X





Sent from my iPhone

 On Feb 14, 2014, at 3:32 PM, dospi...@q.com dospi...@q.com wrote:
 
 
 
 Hello Carl: 
 
 My suggestion is the same as the first time you were on about this. Obtain... 
 beg borrow steal or buy a meter that will read down into the BC band.  You 
 NEED to know where it is resonant..  All the esoteric nonsense about 
 resistance and reactance are meaningless unless you know the frequencies at 
 which the readings are obtained!  You might find the damn thing is 1:1 at 
 1356 kc.. At this point you are shooting in the dark in a dark room..
 
 You may or may not have an adequate ground system, but that doesn't lessen 
 the need to know what it is you have... and you don't.
 
 73 GL
 
 Dean  W5PJR
 Tijeras, NM
 
 
 
 - Original Message -
 From: Carl Braun carl.br...@lairdtech.com
 To: 160 topband@contesting.com
 Sent: Friday, February 14, 2014 4:14:42 PM
 Subject: Topband: Still in search of resonance
 
 List
 
 Some of you may have followed my efforts in trying to shunt feed my 90' 
 Tri-Ex Skyneedle with 20 meter yagi at 93'.  I'm still unable to find any 
 sort of resonance point on the tower.  To refresh everyone's memory here are 
 the specifics:
 
 90' Skyneedle that is 12 round at the base and 4 round at the top
 
 13' of mast out the top
 
 5 element Telrex 20M monobander mounted at the 93' level.  No other antennas 
 on the tower
 
 1 ½ copper pipe as a radial ring that surrounds the concrete base that 
 measures 4' x 8' rectangle.  Three  8' ground rods are connected to the 
 radial ring via 1 copper strap that is .125 thick.
 
 Currently I have 27 14AWG insulated wire radials.  Most of the radials are 
 20' to 50' long with three at 90 to 120' long and four of them connected to 
 my 40M vertical array which have 100 count radials 50' to 100' each.
 
 The tower is grounded to each ground rod via 1 copper strap .125 thick and, 
 as mentioned above, the ground rods are connected to the radial ring with the 
 same strap with copper clad stainless screws.
 
 When I bolted the gamma arm to the tower at the 90' height I dropped a single 
 14AWG wire to the ground where my FLUKE meter read ZERO ohms between the 
 radial ring and the end of the gamma wire with no fluctuations so I'm 
 confident that I have good continuity throughout the tower.
 
 Here are the readings that I saw on the MFJ analyzer with the gamma arm 
 mounted at the (4) points on the tower that are available...
 
 With the gamma arm mounted at 90' and 36 spacing I saw 425 ohms at the end 
 of the drop wire on the MFJ
 
 With the gamma arm mounted at 67' and 36 spacing I saw 380 ohms at the end 
 of the drop wire on the MFJ
 
 With the gamma arm mounted at 46' and 36 spacing I saw 240 ohms at the end 
 of the drop wire on the MFJ
 
 With the gamma arm mounted at 28' and 36 spacing I saw 120 ohms at the end 
 of the drop wire on the MFJ
 
 At all of these points I was able to knock down the R with my honkin' 1050pf 
 cap to some resonance sort of resonance at 1.825 MHz but, as most everyone 
 has indicated, I should be able to find a 50 ohm tap somewhere on the tower.  
 I can't find it.
 
 When I had the gamma arm mounted at the 90' level. I was able to put my baby 
 variable 160pf inline to bring the 425 ohm impedance down to about 60 ohms 
 and the antenna heard very well; especially on the 1700 KHz broadcast band, 
 with a 2.4:1 Vswr.  Similar results could be seen at the other levels too as 
 long as I brought the R down with a variable cap.  Yesterday, with the gamma 
 arm at the 46' level (and 240 ohms on the MFJ) I was able to put the big 
 variable inline to bring the reading to 24 ohms with a TRUE X=0.  With a 22 
 ohm to 50 ohm UNUN, I saw 1.3:1 Vswr on the output of the UNUN.  I worked a 
 W2 in NJ and a W4 in Florida with just the 1000D.  BUT...again...I'm bringing 
 the R down with the capacitor...not finding 50 ohms anywhere on the tower.
 
 Is my radial field so poor that I'm seeing these goofy readings?
 
 Is the single 14AWG too thin causing goofy readings?
 
 I'm back to scratching my head.
 
 Comments from the list?
 
 
 
 Carl AG6X
 
 _
 Topband Reflector Archives - http://www.contesting.com/_topband
_
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Re: Topband: Still in search of resonance

[Carl Braun]

Tom and all

Thanks for the responses. 

I was under the assumption that I would find a 50 ohm tap on the tower but with 
a lot of reactance requiring a cap that would tune out the X but leave the 50 
ohm resistive value in place. 

I knew my tap was too low at 46' when I saw less than 50 ohms with the variable 
cap in place. Same thing when I tapped the tower at 90' and I saw the lowest R 
at 68 ohms with the 160pf only partially meshed. 

With all of the information presented in this thread it appears my best bet is 
to tap the tower at the 67' level while playing with the larger (1050pf) 
variable in series to see what my results are. I have never used the larger cap 
with the tap at 90' or 67'...only the smaller 160pf variable. 

More experimentation tomorrow if I don't burn out the Skyneedle motor with all 
the up and down. 

Thanks and details to follow. 

Carl AG6X

Sent from my iPhone

 On Feb 14, 2014, at 6:01 PM, Tom W8JI w...@w8ji.com wrote:
 
 Hi Carl,
 
 It sounds like you are trying to find 50 ohms on the tower without any series 
 capacitor by looking at R and X. I would not try to do that. The reactance 
 puts you out of range on the MFJ bridge.  You are down to a few bits 
 difference between data points the PIC needs in the MFJ.
 
 Look at this below. You said:
 
 seen at the other levels too as long as I brought the R down with a 
 variable cap.  Yesterday, with the gamma arm at the 46' level (and 240 ohms 
 on the MFJ) I was able to put the big variable inline to bring the reading to 
 24 ohms with a TRUE X=0.  With a 22 ohm to 50 ohm UNUN, I saw 1.3:1 Vswr on 
 the output of the UNUN.  I worked a W2 in NJ and a W4 in Florida with just 
 the 1000D.  BUT...again...I'm bringing the R down with the capacitor...not 
 finding 50 ohms anywhere on the tower
 
 Stop trying to find 50 ohms without the capacitor!
 
 Right now at 46 ft you were at 24 ohms with the capacitor. That should tell 
 you and everyone on this reflector :-)   that you are tapped too low now!
 
 Let's look at this in simple terms. Here is what you said:
 
 When I had the gamma arm mounted at the 90' level. I was able to put my 
 baby variable 160pf inline to bring the 425 ohm impedance down to about 60 
 ohms and the antenna heard very well; especially on the 1700 KHz broadcast 
 band, with a 2.4:1 Vswr.  Similar results could be seen at the other levels 
 too as long as I brought the R down with a variable cap. 
 
 That is NORMAL. You will always need the capacitor. Always. The only way to 
 eliminate the capacitor is to saw your Yagi antenna off the tower so the 
 tower moves above 2 MHz. Then you will probably find a 50j0 tap without any 
 capacitor.
 
 You also might use a large skirt, but why??
 
 Just use a capacitor!!!
 
 If you are trying to eliminate the capacitor, you will have a lot of work to 
 do.
 
 73 Tom 
_
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Re: Topband: Low band noise

[Carl Braun]

Bruce

I work with AC inverters for industrial motor control and their presence 
obsoleted one of my competitor's overhead crane radio control product 
practically overnight.  A simple hand held AM transistor radio was placed 
within 50' of one of these motor Variable Frequency Drive (VFD) controls and 
you could hear the varying frequencies being generated by the IGBT transistors. 
 The competitor remote controls were operating in the 200-400 KHz band.  Pray 
for dead calm winds at SR and SS.

Carl AG6X

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Bill Cromwell
Sent: Tuesday, February 11, 2014 1:39 PM
To: topband@contesting.com
Subject: Re: Topband: Low band noise

Hi Bruce,

I assume your noise is on top band (just a wild guess). I will lay on plans 
this weekend to drive a ways south with the R-599 on 160 meters AND an AM 
broadcast band receiver that allows some directive sniffing to see if the 
windmill farm down that way is um... 'polluting'. I haven't looked that far 
ahead on the weather forecasts. If it's icy or there is a blizzard this old 
goat ain't going there. In the process I suppose I'll find out if my car is 
'clean'. I've been lucky so far.

73,

Bill  KU8H


On 02/11/2014 03:58 PM, Bruce wrote:
 Getting noise from my NW direction. Does not seem to be local. Started 
 wondering what, at distance,  could be causing it. At times it seems to have 
 a rhythm like a motor.

 There are a lot of power generating wind mills showing up.  Checking through 
 Google, they generate DC and convert to  3 phase AC it with an inverter. The 
 frequency and phase of the inverter is controlled with a sample from the 
 power grid.

 Could their inverters have enough sine wave distortion to have harmonic 
 energy?

 So my question is: Does anyone have first hand knowledge of interference on 
 the low bands from  power generator wind mills?

 Bruce-K1FZ
 www.qsl.net/k1fz/beveragenotes.html
 www.qsl.net/k1fz/pennantnotes.html
 _
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Topband: Shunt feeding the Skyneedle

[Carl Braun]

Topbanders

If you followed my post on 'In search of resonance' you'll see that I was 
struggling with feeding a 160m inverted L up close to my 90' Skyneedle.  Tom 
W8JI suggested that I cut back the L to 129' but the same phenomenon was 
seen...that being the VERTICAL section of the inverted L was being completely 
suppressed by the Skyneedle.  At 129' long the antenna resonated nicely on 8.2 
MHz or so...indicating the vertical section was still suppressed and the top 
29' was resonating.  With this in mind I decided to run a shunt wire from the 
top to see where the antenna resonates.  Here's what I found...

The Skyneedle is 90' tall and has a 13' mast sticking out the top that mounts a 
Telrex 20M546 yagi on a 15m boom.

The aluminum gamma arm was attached at the 90' level at 24 away from the tower 
and held in place by PVC standoffs.  See attached photo if the reflector lets 
me post an attachment.

The MFJ read 380 ohms at 1825 and the X is way off the scale.  I inserted an EF 
Johnson 10-160pf air variable capacitor at the base...in series...and was able 
to tune the antenna to 60 ohms and the X=22.  If I played with the cap there 
was a real sharp drop in reactance showing X=12.  The air variable was about ¾ 
meshed.

Here are the other resonant points...

15.8 MHz X=0 R=37 with pos and neg reactance on either side of X=0.  This freq 
showed the sharpest dip of any of the three.

Next was 10.6 MHz X=0 R=23 with pos and neg reactance on either side of X=0.

The last real dip I saw was at 5.3 Mhz with X=0 R=10

No dips below these frequencies but as I stated earlier I tuned the MFJ 259 to 
1825 and then played with the variable cap where I saw the big drop in 
impedance. (58-60 ohms at X=12 to 22.

Here are my questions for the gurus...

Do I attempt to match the antenna using a gamma match by tapping the Skyneedle 
at the 67' level to see how it reacts with regards to R and X?  (Note - I 
cannot vary my gamma arm height as this is a tubular tower and there are few 
places to bolt on the gamma arm...90', 67', 46' and 25' with the latter being 
the crows nest platform).


Or


Can I leave the gamma arm at 90' and rely on an Omega match to tune the antenna?



Carl

_
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Re: Topband: Shunt feeding the Skyneedle

[Carl Braun]

Tom and group

The SWR is 2.4:1 at 1822

I have an old Heathkit tuner that has a pair of air variables that I may 
temporarily yank to experiment with gamma vs. omega matching.  I've got a wing 
wang capacitance meter that would tell me the values once I get something to 
resonate.

The 160pf Johnson variable is 3/4 meshed so I don't see additional C being 
needed in series.  I think I will have to add a parallel C to get it down to 50 
ohms and x=0.  If I can get the tower to 50/x=0 then I'll substitute a vac 
variable in for the Johnson.  The Johnson SHOULD work as a parallel cap as it's 
good for 7KV according to the Johnson literature.  See pic.

Also, I've been basing a lot of my values (tap height and gamma spacing) on 
ON4UNs charts.  But I found some English amateur who did a study on 
gamma/Omega/Beta matching and found that ON4UNs calculations are up to 2X out 
of whack.  I also found an old article on shunt feeding towers from Ham Radio 
magazine that gave tap height, gamma spacing and C curves. His calculations 
were off quite a bit as compared to ON4UNs.  I attributed this to computer 
modeling vs. none back in the day and would tend to think the modeling results 
are more accurate.  See attached article.  I see a good 20-40 degrees 
difference between the old school article and ON4UNs calculations.

I don't do any modeling though I'd like to try EZNEC or? one of these days to 
see what my various antennas really look like.

So, i'm assuming you're suggesting that I drop the gamma arm down to the 67' 
level and see what the impedance looks like?  If so, I'm guessing the series C 
required to tune would increase in value?

Please advise

Thanks

Carl AG6X


-Original Message-
From: Tom W8JI [mailto:w...@w8ji.com] 
Sent: Monday, February 03, 2014 8:58 AM
To: Carl Braun; '160'
Subject: Re: Shunt feeding the Skyneedle

the vertical section was still suppressed and the top 29' was resonating. 
With this in mind I decided to run a shunt wire from the top to see where 
the antenna resonates.  Here's what I found..

I was afraid the tower was messing up the L. This is what happens when they 
are are nearly resonant.

You can't measure tower resonance with a drop wire. The drop wire is a stub 
or shorted transmission line in parallel with the common mode impedance 
presented by the drop wire and tower combination. It is just a mess of stuff 
going on.

 
The MFJ read 380 ohms at 1825 and the X is way off the scale.  I inserted an 
EF Johnson 10-160pf air variable capacitor at the base.in series.and was 
able to tune the antenna to 60 ohms and the X=22.  If I played with the cap 
there was a real sharp drop in reactance showing X=12.  The air variable was 
about ¾ meshed.



Reducing the lenth (tap point height) of the drop wire is a better way to 
get impedance right. Or, better still, use a multiple wire drop to make the 
drop diameter look larger. That will reduce Q, require more C, and should 
reduce impedance.

You are so close at 60 ohms I would not worry. Adjust the cap for lowest 
SWR. What is the SWR??



_
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Re: Topband: Shunt feeding the Skyneedle

[Carl Braun]

ON4UNs graph in his book states that my 27m tower with 13' mast and 5 ele 20m 
monobander (@ 28m high) is good for about 115 degrees. Other old school 
references place it at 140 degrees. 

Per my past posts I have a gamma arm at 90' and 25-28 inches from the tower. I 
have 380 to 400 ohms at the bottom of the gamma wire to gnd. If I insert my EFJ 
160pf air variable I can get the antenna to tune to 60 ohms and X=20 or so. 

This morning I was copying Asian stations on 160 and the tuned into the BC 
band. Using my 40m vertical array as a reference I switched back and forth 
between my shunt fed tower and the array. At 600AM the signal strength on the 
40m antennas were stronger. At 1200AM the array and the shunted tower were 
equal at 1700AM ESPN radio was a good 30 to 40db stronger on the shunted tower. 
Then the sensitivity decreased as I approached 1800 but the tower was still 
20db stronger than the 40m antenna when listening to the FT5 pileup. 

More experimentation with gamma arm placement today

Carl AG6X

Sent from my iPhone

 On Feb 4, 2014, at 8:13 AM, ZR z...@jeremy.mv.com wrote:
 
 Any idea how much top loading that 5 el 46' boom monster contributes?
 
 At a prior QTH in the 80's I had a 90' 25G toploaded with a 10-15-20M stack 
 of PV-4 monobanders and about 18' of mast. The 20M boom was 40' and the tower 
 resonated at 1620KHz  if I remember. Sure worked great once I figured out 
 that 60 radials werent so hot over sand and added a mesh extending 50' from 
 the base.
 
 The gamma rod was the shield of 3/4 CATV coax about 2' from the tower and 
 the best tap point was around 60' if I remember.
 
 Carl
 KM1H
 
 
 - Original Message - From: Carl Braun carl.br...@lairdtech.com
 To: '160' topband@contesting.com
 Cc: 'Tom W8JI' w...@w8ji.com
 Sent: Monday, February 03, 2014 11:17 AM
 Subject: Topband: Shunt feeding the Skyneedle
 
 
 
 Topbanders
 
 If you followed my post on 'In search of resonance' you'll see that I was 
 struggling with feeding a 160m inverted L up close to my 90' Skyneedle.  Tom 
 W8JI suggested that I cut back the L to 129' but the same phenomenon was 
 seen...that being the VERTICAL section of the inverted L was being completely 
 suppressed by the Skyneedle.  At 129' long the antenna resonated nicely on 
 8.2 MHz or so...indicating the vertical section was still suppressed and the 
 top 29' was resonating.  With this in mind I decided to run a shunt wire from 
 the top to see where the antenna resonates.  Here's what I found...
 
 The Skyneedle is 90' tall and has a 13' mast sticking out the top that mounts 
 a Telrex 20M546 yagi on a 15m boom.
 
 The aluminum gamma arm was attached at the 90' level at 24 away from the 
 tower and held in place by PVC standoffs.  See attached photo if the 
 reflector lets me post an attachment.
 
 The MFJ read 380 ohms at 1825 and the X is way off the scale.  I inserted an 
 EF Johnson 10-160pf air variable capacitor at the base...in series...and was 
 able to tune the antenna to 60 ohms and the X=22.  If I played with the cap 
 there was a real sharp drop in reactance showing X=12.  The air variable was 
 about ¾ meshed.
 
 Here are the other resonant points...
 
 15.8 MHz X=0 R=37 with pos and neg reactance on either side of X=0.  This 
 freq showed the sharpest dip of any of the three.
 
 Next was 10.6 MHz X=0 R=23 with pos and neg reactance on either side of X=0.
 
 The last real dip I saw was at 5.3 Mhz with X=0 R=10
 
 No dips below these frequencies but as I stated earlier I tuned the MFJ 259 
 to 1825 and then played with the variable cap where I saw the big drop in 
 impedance. (58-60 ohms at X=12 to 22.
 
 Here are my questions for the gurus...
 
 Do I attempt to match the antenna using a gamma match by tapping the 
 Skyneedle at the 67' level to see how it reacts with regards to R and X? 
 (Note - I cannot vary my gamma arm height as this is a tubular tower and 
 there are few places to bolt on the gamma arm...90', 67', 46' and 25' with 
 the latter being the crows nest platform).
 
 
 Or
 
 
 Can I leave the gamma arm at 90' and rely on an Omega match to tune the 
 antenna?
 
 
 
 Carl
 
 _
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 -
 No virus found in this message.
 Checked by AVG - www.avg.com
 Version: 2014.0.4259 / Virus Database: 3684/7058 - Release Date: 02/03/14
 
 
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Re: Topband: Shunt feeding the Skyneedle

[Carl Braun]

Topbanders

Well, after experimenting with shortening the gamma wire from the bottom I saw 
NO changes on the MFJnone.  So, option two was to lower the whole tower 
down and remove the gamma arm from the 90' level and remount it at the 67' 
level.  That done I cranked the tower back up and looked at the R at the bottom 
of the gamma wire.  I saw 380 to 400 Ohms...the same reading that I saw when 
the gamma arm was at 90'!!!  Frustrating.

Here's what changed though...when I had the gamma arm at 90' with the 14 gauge 
gamma wire 24 away from the tower I was able to insert my Johnson 60-160pf 
variable cap in series with the gamma wire to get approx 58-60 ohms at X=20.  
The cap was 2/3 meshed at this point.  

NOW that I've lowered the gamma arm to the 67' level...I insert my variable cap 
and the antenna resonates at 1.970 MHz with R=36 ohms and X=0.  For some odd 
reason the MFJ SWR reading shows 1.0:1 with this 36 ohm reading and, inside the 
shack, the Ft1000D shows 1.0:1 swr from 1.988 to 1.950 and a 1.5:1 range of 
2.007 to 1.930.

It now appears that the antenna is a bit short but why am I seeing these crazy 
high resistance readings with no variable cap in line?

How can I lower the resonant freq without moving the gamma arm up?  Increase 
the spacing of the gamma wire from the tower? Add more radials?

I was going to build a three conductor wire cage with the wires spaced 10 
apart or so once I had an idea where the antenna resonates.  Would a fatter 
gamma trio drop the resonant freq or just change the capacitance value of the 
antenna?

Lots of questions but I feel I'm making progress as the FLAT SWR high in the 
band indicates the antenna wants to work well but I need to lower the resonant 
frequency.

Comments please

Thanks

Carl AG6X




-Original Message-
From: ZR [mailto:z...@jeremy.mv.com] 
Sent: Tuesday, February 04, 2014 8:13 AM
To: Carl Braun; '160'
Cc: 'Tom W8JI'
Subject: Re: Topband: Shunt feeding the Skyneedle

Any idea how much top loading that 5 el 46' boom monster contributes?

At a prior QTH in the 80's I had a 90' 25G toploaded with a 10-15-20M stack 
of PV-4 monobanders and about 18' of mast. The 20M boom was 40' and the 
tower resonated at 1620KHz  if I remember. Sure worked great once I figured 
out that 60 radials werent so hot over sand and added a mesh extending 50' 
from the base.

The gamma rod was the shield of 3/4 CATV coax about 2' from the tower and 
the best tap point was around 60' if I remember.

Carl
KM1H


- Original Message - 
From: Carl Braun carl.br...@lairdtech.com
To: '160' topband@contesting.com
Cc: 'Tom W8JI' w...@w8ji.com
Sent: Monday, February 03, 2014 11:17 AM
Subject: Topband: Shunt feeding the Skyneedle



Topbanders

If you followed my post on 'In search of resonance' you'll see that I was 
struggling with feeding a 160m inverted L up close to my 90' Skyneedle.  Tom 
W8JI suggested that I cut back the L to 129' but the same phenomenon was 
seen...that being the VERTICAL section of the inverted L was being 
completely suppressed by the Skyneedle.  At 129' long the antenna resonated 
nicely on 8.2 MHz or so...indicating the vertical section was still 
suppressed and the top 29' was resonating.  With this in mind I decided to 
run a shunt wire from the top to see where the antenna resonates.  Here's 
what I found...

The Skyneedle is 90' tall and has a 13' mast sticking out the top that 
mounts a Telrex 20M546 yagi on a 15m boom.

The aluminum gamma arm was attached at the 90' level at 24 away from the 
tower and held in place by PVC standoffs.  See attached photo if the 
reflector lets me post an attachment.

The MFJ read 380 ohms at 1825 and the X is way off the scale.  I inserted an 
EF Johnson 10-160pf air variable capacitor at the base...in series...and was 
able to tune the antenna to 60 ohms and the X=22.  If I played with the cap 
there was a real sharp drop in reactance showing X=12.  The air variable was 
about ¾ meshed.

Here are the other resonant points...

15.8 MHz X=0 R=37 with pos and neg reactance on either side of X=0.  This 
freq showed the sharpest dip of any of the three.

Next was 10.6 MHz X=0 R=23 with pos and neg reactance on either side of X=0.

The last real dip I saw was at 5.3 Mhz with X=0 R=10

No dips below these frequencies but as I stated earlier I tuned the MFJ 259 
to 1825 and then played with the variable cap where I saw the big drop in 
impedance. (58-60 ohms at X=12 to 22.

Here are my questions for the gurus...

Do I attempt to match the antenna using a gamma match by tapping the 
Skyneedle at the 67' level to see how it reacts with regards to R and X? 
(Note - I cannot vary my gamma arm height as this is a tubular tower and 
there are few places to bolt on the gamma arm...90', 67', 46' and 25' with 
the latter being the crows nest platform).


Or


Can I leave the gamma arm at 90' and rely on an Omega match to tune the 
antenna?



Carl

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Topband Reflector Archives - http

Re: Topband: Shunt feeding the Skyneedle

[Carl Braun]

Thanks for the input Tom

The only variable cap I have is the EF Johnson which is 60-160pf. I have some 
ham radio stuff at my parents house not the least is a Jennings 1000pf vac 
variable rated at 5KV or 7.5kv. I was hoping to use that with a 12v motor for 
QSYing up the band for contesting. I'll have to ask mom to send it to CA in a 
pkg with some cookies. 

When the gamma arm was at 90' I was able to add 160pf to get a resonance point 
around 1825 but the resistance was still high at 58-60 and X was 20++. Maybe 
the big vacuum cap  would bring that R and X down to where it needs to be. 

ON4UNs figure 9-85 on page 9-71 of his third edition shows that a tower that is 
electrical 110 to 130 degrees should have a tap height around 20 meters and a 
matching cap of 400pf. That being said it may be a good idea to get the vac 
variable into service. I would assume I would want to raise the gamma arm back 
up to 90' as it resonated closer to 1825 than the latest iteration which shows 
a Fr near
1.977 
 
 
Sent from my iPhone

 On Feb 4, 2014, at 6:40 PM, Tom W8JI w...@w8ji.com wrote:
 
 Here's what changed though...when I had the gamma arm at 90' with the 14 
 gauge gamma wire 24 away from the tower I was able to insert my Johnson 
 60-160pf variable cap in series with the gamma wire to get approx 58-60 ohms 
 at X=20.  The cap was 2/3 meshed at this point.  
 
 That's the right way. You have to cancel the reatcance of the drop arm to get 
 a good reading. Maybe you need a larger capacitor to hit the bottom of the 
 band? Resistance normally goes up in a case like yours as frequency is 
 drecreased.
 
 NOW that I've lowered the gamma arm to the 67' level...I insert my 
 variable cap and the antenna resonates at 1.970 MHz with R=36 ohms and X=0. 
 For some odd reason the MFJ SWR reading shows 1.0:1 with this 36 ohm reading 
 and, inside the shack, the Ft1000D shows 1.0:1 swr from 1.988 to 1.950 and a 
 1.5:1 range of 2.007 to 1.930
 
 What does more capacitance do?
 
 It now appears that the antenna is a bit short but why am I seeing these 
 crazy high resistance readings with no variable cap in line?
 
 You should see them. The MFJ detector is a 50 ohm bridge. It will overflow 
 and give all kinds of goofy readings when impedance is far away from 50 ohms.
 
 How can I lower the resonant freq without moving the gamma arm up? Increase 
 the spacing of the gamma wire from the tower? Add more radials?
 
 I would have left it at the top and shorted the wire to the tower at 
 different places until I found the sweet spot. But you have to dip the 
 reactance out to really know what you have.
 
 
 I was going to build a three conductor wire cage with the wires spaced 10 
 apart or so once I had an idea where the antenna resonates.  Would a fatter 
 gamma trio drop the resonant freq or just change the capacitance value of the 
 antenna?
 
 A fatter shunt wire will lower reactance and resistance. You will need more 
 C, and the tuned resistance will be a bit lower. 
_
Topband Reflector Archives - http://www.contesting.com/_topband

Re: Topband: In search of resonance

[Carl Braun]

Thanks to all who responded to my post

I will consider all of the ideas that were presented including improving the 
ground radials. That's a given.

I have an ICE broadcast filter for RX...can this be of any use with the MFJ for 
analyzing the antenna?

Shall I drop the 40m verticals or open them at the base to see if any readings 
change?

The good news is the end of the L is run through a pulley attached to a 70' 
palm tree.  I'll lower the end of the wire down and fold it back a few feet 
until I can get something to resonate. Stay tuned (pun intended).

What's strange is that I had a version of this L up before with 2 temp radials 
lying on the ground.  I used a REYCO trap at 67' and ran the rest of the L up 
20' to the top of the tower and then out 15 to 20 ft.  The REYCO trap has some 
inductance but the whole 160 portion wasn't much over 100' and the thing 
resonated on 80 too. The vertical portion was much closer to the tower than it 
is now...maybe 15-18 instead of 36 now.  My Reyco trap has since bit the dust 
and Unadilla isn't making any more for at least another month.

I'll post some results later after folding back some wire.

Tnx again

Carl AG6X




From: donov...@starpower.net [mailto:donov...@starpower.net]
Sent: Thursday, January 30, 2014 7:59 AM
To: topband@contesting.com
Subject: Re: Topband: In search of resonance

Carl,

Are you sure your MFJ meter isn't being overloaded by a broadcast station?
Thats a very common problem especially on 160 meters.

73
Frank
W3LPL


From: Carl Braun carl.br...@lairdtech.com
To: topband@contesting.com
Sent: Thursday, January 30, 2014 4:16:53 AM
Subject: Topband: In search of resonance


Hello to the group

I'm a newbie to 160 having only participated in various contests over the 
course of the last two years.  I used an 80 meter aluminum tube vertical with a 
Reyco trap affixed to the top with a horizontal L: wire heading over to the 
palm tree.  I've since converted that antenna into a pair of 40M verticals so 
I'm focusing my efforts on getting a resonant antenna on 60 and especially 160.

Here's the hardware I'm working with...

90' Tri Ex Skyneedle tower with a Telrex 20 meter 5-element yagi on a 45' boom 
at 94'.

Inverted L wire runs parallel to the tower and is spaced at 36 up to 85' and 
then out approx 60' or so.

The tower is grounded via copper strap to three ground rods that are bonded to 
1 ½ copper pipe that circles the perimeter of my tower and control panel base. 
The perimeter copper pipe is a 4' x 8' rectangle that currently has 16 radials 
screwed to it.  Three of those radials are tied into my 40M phased array ground 
radial system with some of the radials as short as 30' and others as long as 
100'.  The ground screen for my 40M array uses 100 radials each 60-90' long.  
I'm adding radials as I have time.  Half of the 16 radials are multi conductor 
rotor control cable that fans out to affix to the radial ring then converge 
back together for 10' across the driveway and then fan out.  I do this to 
eliminate a lot of individual wires crossing my secondary driveway.

I cannot get the inverted L to provide a dip on my MFJ 259 analyzer anywhere in 
the 160 meter band.  I get dips at 8.2 MHz (R=36 ohms X=0) with reactance on 
each side of X=0.  At 5 MHz R=40 ohms X=0 with reactance on each side of X=0.  
I cant get any significant dips neat the 80 or 160 band.  However, when I 
approach 1.750MHz the resistance drops to 6 ohms and X is off the scale...at 
1.825 I'm at 10 ohms and X is off the scale.  Its as if my 140+ feet of wire is 
resonant on 8MHz.

Also, I've experimented with shunt feeding the tower to see where the thing 
would resonate but got similar results.  ON4UN says my 90' tower and 5 ele yagi 
should yield an antenna that is 110 to 115 degrees in total length so I 
followed his guidelines and tapped the tower at 67' with a gamma wire spaced at 
36 .  The tower had multiple dips at 27 MHz, 20 MHz, 14 MHz and at 7.5 MHz the 
resistance dropped to 6 ohms...the same low resistance I' m now seeing on the L 
at 1.750 or so.  No dips were observed at 3.5 or 1.8 MHz. I plan to experiment 
with a gamma wire that goes all the way to the top of the tower to see where it 
resonates...if its still high in freq maybe I should consider an Omega match

So all of that being said...why cant I find a resonant frequency on 160 with 
this L?  Am I still too long?  Is the tower causing that much interaction? I'd 
rather not cut the L long and insert a variable cap...I want it resonant at 
1820 so I can use an unun to match the impedance and then run it into the shack.

Any suggestions on getting the antenna to work?

Thanks in advance for any help


Carl AG6X

_
Topband Reflector Archives - http://www.contesting.com/_topband

_
Topband Reflector Archives - http://www.contesting.com/_topband

Topband: In search of resonance

[Carl Braun]

Hello to the group

I'm a newbie to 160 having only participated in various contests over the 
course of the last two years.  I used an 80 meter aluminum tube vertical with a 
Reyco trap affixed to the top with a horizontal L: wire heading over to the 
palm tree.  I've since converted that antenna into a pair of 40M verticals so 
I'm focusing my efforts on getting a resonant antenna on 60 and especially 160.

Here's the hardware I'm working with...

90' Tri Ex Skyneedle tower with a Telrex 20 meter 5-element yagi on a 45' boom 
at 94'.

Inverted L wire runs parallel to the tower and is spaced at 36 up to 85' and 
then out approx 60' or so.

The tower is grounded via copper strap to three ground rods that are bonded to 
1 ½ copper pipe that circles the perimeter of my tower and control panel base. 
The perimeter copper pipe is a 4' x 8' rectangle that currently has 16 radials 
screwed to it.  Three of those radials are tied into my 40M phased array ground 
radial system with some of the radials as short as 30' and others as long as 
100'.  The ground screen for my 40M array uses 100 radials each 60-90' long.  
I'm adding radials as I have time.  Half of the 16 radials are multi conductor 
rotor control cable that fans out to affix to the radial ring then converge 
back together for 10' across the driveway and then fan out.  I do this to 
eliminate a lot of individual wires crossing my secondary driveway.

I cannot get the inverted L to provide a dip on my MFJ 259 analyzer anywhere in 
the 160 meter band.  I get dips at 8.2 MHz (R=36 ohms X=0) with reactance on 
each side of X=0.  At 5 MHz R=40 ohms X=0 with reactance on each side of X=0.  
I cant get any significant dips neat the 80 or 160 band.  However, when I 
approach 1.750MHz the resistance drops to 6 ohms and X is off the scale...at 
1.825 I'm at 10 ohms and X is off the scale.  Its as if my 140+ feet of wire is 
resonant on 8MHz.

Also, I've experimented with shunt feeding the tower to see where the thing 
would resonate but got similar results.  ON4UN says my 90' tower and 5 ele yagi 
should yield an antenna that is 110 to 115 degrees in total length so I 
followed his guidelines and tapped the tower at 67' with a gamma wire spaced at 
36 .  The tower had multiple dips at 27 MHz, 20 MHz, 14 MHz and at 7.5 MHz the 
resistance dropped to 6 ohms...the same low resistance I' m now seeing on the L 
at 1.750 or so.  No dips were observed at 3.5 or 1.8 MHz. I plan to experiment 
with a gamma wire that goes all the way to the top of the tower to see where it 
resonates...if its still high in freq maybe I should consider an Omega match

So all of that being said...why cant I find a resonant frequency on 160 with 
this L?  Am I still too long?  Is the tower causing that much interaction? I'd 
rather not cut the L long and insert a variable cap...I want it resonant at 
1820 so I can use an unun to match the impedance and then run it into the shack.

Any suggestions on getting the antenna to work?

Thanks in advance for any help


Carl AG6X

_
Topband Reflector Archives - http://www.contesting.com/_topband

Topband: 160m L or Shunt?

[Carl Braun]

All

I'm working on installing an 80/160 inverted L that will be approximately 165' 
in total length with the vertical portion being 88' tall and the rest of the 
wire (77') running out to a 80' tall palm tree.  This will give me 
approximately 5/8w on 80 and 5/16w on 160 and will allow me to use a single 
antenna wire into my matching networks at the base.

I've thought about shunt feeding the tower and have researched the archives 
here to get some ideas but I have two concerns:

1)   I'm using a Tri Ex TM 490 (90') Skyneedle and am concerned about good 
grounding between the tubular sections if I was to shunt feed the thing. I'm 
not crazy about running a continuity wire down the length of the needle.  
Thus my interest with an inverted L off of the tower.  I've constructed a 1 ½ 
copper pipe around the base of the needle and the control panel that measures 
6' x 4' that will act as my radial plate.  I plan on having 50 1/8 wl radials 
and 10 ¼ wl ground radials when finished
2)  I was unable to get a real feel for where the tower resonates.  I have 
a 5 element Telrex monster on top of the Needle that uses grounded elements and 
I'm fairly sure the antenna resonates below the 160M band.  I'm assuming this 
as I disconnected the coax where the Telrex feeds into my control panel at the 
base of the Needle and placed an MFJ analyzer between the braid of the yagi 
coax and GND.  The MFJ was beginning to dip when I ran out of real estate on 
the meter...the MFJ bottoms out at @1750KHz.  I'm assuming the tower and 
antenna resonate at @1700KHz
3)  I have concerns that I could not resonate the tower on 80m if I shunted 
it

Considering these items I wanted to keep things tidy so I'm installing the 
inverted L off of the tower (36) and starting from there.

Here are my questions:

1)   Will I have to de-tune the tower in order to get the L to resonate on 
80 and 160?
2)   Am I better off continuing to try and find a resonant sweet spot on 
the tower and shunt instead of an inverted L?
3)   I would expect 10-20 ohms at 160 and approx 40-60 ohms on 80 with the 
full sized 165' vertical.  Am I close?

Comments from the gurus?

Tnx de AG6X



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